diff --git a/competitive_programming/abctripletatc.cpp b/competitive_programming/abctripletatc.cpp
new file mode 100644
index 0000000..bb6b61e
--- /dev/null
+++ b/competitive_programming/abctripletatc.cpp
@@ -0,0 +1,23 @@
+#include <iostream>
+using namespace std;
+int main ()
+{
+    long long n;
+    cin >> n;
+    long long a, b, c, triplets = 0;
+    for ( a = 1; a <= n; a++)
+    {
+        for ( b = a; b <= n; b++)
+        {
+            for ( c = b; c <= n; c++)
+            {
+                if (a*b*c <= n) triplets++;
+            }
+            
+        }
+        
+    }
+    
+    cout << triplets << endl;
+
+}
diff --git a/competitive_programming/ancientcivicf.cpp b/competitive_programming/ancientcivicf.cpp
new file mode 100644
index 0000000..f877eed
--- /dev/null
+++ b/competitive_programming/ancientcivicf.cpp
@@ -0,0 +1,42 @@
+#include <iostream>
+using namespace std;
+int main()
+{
+    int t;
+    cin >> t;
+    while (t--)
+    {
+        int n, l, i = 0, j = 0;
+        cin >> n >> l;
+        int deci[n];
+        while (n--)
+        {
+
+            cin >> deci[i];
+            i++;
+        }
+
+        int bina[n][l];
+        for (i = 0; i < n; i++)
+        {
+            for (j = 0; j < l; j++)
+            {
+                bina[i][j] = 0;
+            }
+        }
+        for (i = 0; i < n; i++)
+        {
+
+            for (j = l-1; j >= 0; j--)
+            {
+                if (deci[n])
+                {
+                    bina[i][j] = deci[n] % 2;
+                    deci[n] = deci[n] / 2;
+                }
+                cout << bina[i][j];
+            }
+            cout << endl;
+        }
+    }
+}
diff --git a/competitive_programming/average.cpp b/competitive_programming/average.cpp
new file mode 100644
index 0000000..bfc1d96
--- /dev/null
+++ b/competitive_programming/average.cpp
@@ -0,0 +1,42 @@
+#include <iostream>
+#include <string>
+#include <sstream>
+using namespace std;
+int main()
+{
+    int t, n, c = 0;
+    cin >> t;
+    while (t--)
+    {
+        float outs = 0, runs = 0;
+        float ans;
+        c++;
+        cin >> n;
+        while (n--)
+        {
+            string run;
+            cin >> run;
+            int x = run.size() - 1;
+            if (run[x] != '*')
+                outs++;
+            float run2;
+            stringstream ss;
+            ss << run;
+            ss >> run2;
+            runs += run2;
+        }
+        if (outs == 0) 
+            cout << "Case " << c << ":" << " " << -1 << endl;
+        else 
+        {
+            ans = runs / outs;
+            if (ans - int(ans) > 0)
+            {
+                cout << "Case " << c << ":" << " " << -1 << endl;
+            }
+            else
+                cout << "Case " << c << ":" << " " << int(ans) << endl;
+        }
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/buildingareaguess.cpp b/competitive_programming/buildingareaguess.cpp
new file mode 100644
index 0000000..4d4f5ef
--- /dev/null
+++ b/competitive_programming/buildingareaguess.cpp
@@ -0,0 +1,25 @@
+//ac
+#include <iostream>
+using namespace std;
+int main()
+{
+    int n, i, rightguess = 0;
+    cin >> n;
+    int s, b, zerornot;
+    for (i = 0; i < n; i++)
+    {
+        cin >> s;
+
+        for (b = 1; b <= (s - 3) / 7; b++) // for a = 1 we get the highest number of b
+        {
+            zerornot = (s - 3 * b) % (4 * b + 3); // determining --> is it a natural number or fractional 
+            if (zerornot == 0)
+            {
+                rightguess++;
+                break;
+            }
+        }
+    }
+    cout << n - rightguess << endl;
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/cellguesscf.cpp b/competitive_programming/cellguesscf.cpp
new file mode 100644
index 0000000..eb3ef50
--- /dev/null
+++ b/competitive_programming/cellguesscf.cpp
@@ -0,0 +1,21 @@
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    long long t , n, m;
+    cin >> t;
+    for(int i = 0 ; i < t ; i++){
+        cin >> n >> m;
+        if (n==m==1)
+            cout << 0 << endl;
+        else if (n<m){
+            cout << n << endl;
+        }
+        else{
+            cout << m << endl;
+        }
+        
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/chal.py b/competitive_programming/chal.py
new file mode 100644
index 0000000..2b11a8b
--- /dev/null
+++ b/competitive_programming/chal.py
@@ -0,0 +1,22 @@
+import random
+
+def encrypt(plaintext):
+    ciphertext = ''
+    for letter in plaintext:
+        i = ALPHA.index(letter)
+        c = (a*i + b) % m
+        ciphertext += ALPHA[c]
+    return ciphertext
+
+
+ALPHA = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ{}_ #"
+m = len(ALPHA)
+a = random.randrange(1, m)
+b = random.randrange(1, m)
+
+message = open("message.txt").read().replace('\n', '')
+cipher = encrypt(message)
+
+with open("cipher.txt", 'w') as f:
+    for i in range(0,len(cipher),64):
+        f.write( cipher[i:i+64]+'\n' )
diff --git a/competitive_programming/continuefraction.cpp b/competitive_programming/continuefraction.cpp
new file mode 100644
index 0000000..23c2f1b
--- /dev/null
+++ b/competitive_programming/continuefraction.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#include <iomanip>
+int i;
+using namespace std;
+int frac(int x, int y)
+{
+    int z;
+    z = x / y;
+    cout << z << " ";
+    int rem;
+    rem = x%y;
+	if(rem!=1)
+    	frac(y, rem);
+	else
+		cout << y;
+	return 0;
+}
+
+int howmuch(int x, int y)
+{
+	i++;
+    int rem;
+    rem = x%y;
+	if(rem!=1)
+    	howmuch(y, rem);
+	else
+		cout << i << " ";
+	return 0;
+}
+
+int main()
+{
+    int t;
+    cin >> t;
+    while (t--)
+    {
+		i = 0;
+        int x, y, rem;
+        cin >> x >> y;
+		howmuch(x,y);
+        frac(x, y);
+        cout << endl;
+    }
+}
diff --git a/competitive_programming/daily_star.py b/competitive_programming/daily_star.py
new file mode 100644
index 0000000..77ce0bd
--- /dev/null
+++ b/competitive_programming/daily_star.py
@@ -0,0 +1,9 @@
+import requests
+from bs4 import BeautifulSoup
+daily_star = requests.get('https://www.thedailystar.net')
+parsed_html = BeautifulSoup(daily_star.text, 'html.parser')
+headlines = parsed_html.find_all('h3')
+for i in headlines: 
+    if len(i.text.strip()) > 0:
+        print(i.text) 
+        
\ No newline at end of file
diff --git a/competitive_programming/deviationcf.cpp b/competitive_programming/deviationcf.cpp
new file mode 100644
index 0000000..d0e8571
--- /dev/null
+++ b/competitive_programming/deviationcf.cpp
@@ -0,0 +1,39 @@
+#include <iostream>
+using namespace std;
+int main()
+{
+    int t, x = 6;
+    cin >> t;
+    int a[3];
+    for (int i = 0; i < t; i++)
+    {
+        
+        cin >> a[0] >> a[1] >> a[2];
+        while (x--)
+        {
+            if (a[0] + a[2] - 2 * a[1] == 0)
+            {
+                cout << 0 << endl;
+                break;
+            }
+            else if (abs(a[0] + a[2] - 2 * a[1]) == 1)
+            {
+                cout << 1 << endl;
+                break;
+            }
+            else
+            {
+                if (a[0] + a[2] - 2 * a[1] > 1)
+                {
+                    a[1] = a[1] + 1;
+                    a[0] = a[0] - 1;
+                }
+                else
+                {
+                    a[1] = a[1] - 1;
+                    a[0] = a[0] + 1;
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/competitive_programming/distancemanhattancf.cpp b/competitive_programming/distancemanhattancf.cpp
new file mode 100644
index 0000000..b66b24e
--- /dev/null
+++ b/competitive_programming/distancemanhattancf.cpp
@@ -0,0 +1,26 @@
+#include <iostream>
+#include <cmath>
+
+int main() {
+    float t, x, y, a, b, d_bcac;
+    std::cin >> t;
+    for (int i=0; i<t; i++)
+    {
+        std::cin >> x >> y;
+        d_bcac = (x+y)/2; //if abs used then d_bcac won't be a float number
+        if(d_bcac - round(d_bcac) == 0)
+        {
+            for (int i=0; i<=d_bcac; i++)
+            {
+                a=i;
+                b=d_bcac-i;
+                if (abs(a-x) +abs(b-y) == d_bcac)
+                break;
+            }    
+            std::cout << a << " " << b << "\n";
+        }
+        //std::cout << (x+2*d_bcac-y)/2 << " " << (y+2*d_bcac-x)/2 << "\n";
+        else 
+        std::cout << -1 << " " << -1 << "\n";
+    }
+}
\ No newline at end of file
diff --git a/competitive_programming/divanstorecf.cpp b/competitive_programming/divanstorecf.cpp
new file mode 100644
index 0000000..f269c0d
--- /dev/null
+++ b/competitive_programming/divanstorecf.cpp
@@ -0,0 +1,31 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+    int t, i;
+    cin >> t;
+    for(i = 0 ; i < t ; i++){
+        int n, l, r, k, a = 0, spended =0, chocolates = 0;
+        cin >> n >> l >> r >> k;
+        int chocoprice[n];
+        for (i = 0; i < n; i++) cin >> chocoprice[i];
+        for ( i = 0; i < n; i++)
+        {
+            if(chocoprice[i] >= l && chocoprice[i] <= r) a++;
+        }
+        int buyable[a];
+        for (int i = 0; i < n; i++)
+        {
+            if(chocoprice[i] >= l && chocoprice[i] <= r) buyable[a] = chocoprice[i];
+        }
+        int asize = sizeof(buyable) / sizeof(buyable[0]); 
+        sort(buyable, buyable + asize);
+        for ( i = 0; i < a; i++)
+        {
+            spended += buyable[i];
+            if (spended <= k) chocolates++;
+        }
+        cout << chocolates << endl;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/divmulcf.cpp b/competitive_programming/divmulcf.cpp
new file mode 100644
index 0000000..e838ee0
--- /dev/null
+++ b/competitive_programming/divmulcf.cpp
@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+    int t, i, j;
+    cin >> t;
+    for (j = 0; j < t; j++)
+    {
+        int n;
+        cin >> n;
+        int a[n], odd[n], mult2 = 0, highestodd = 1, highestoddindex = 0, highwithodd, highmult = 0, power;
+        long long sum;
+        if (n == 1)
+        {
+            cin >> a[0];
+            cout << a[0] << endl;
+        }
+        else
+        {
+            for (i = 0; i < n; i++)
+            {
+                cin >> a[i];
+                odd[i] = a[i];
+                while (1)
+                {
+                    if (odd[i] % 2 == 1)
+                        break;
+                    else
+                    {
+                        odd[i] = odd[i] / 2;
+                        mult2++;
+                    }
+                }
+                if (odd[i] > highestodd)
+                {
+                    highestodd = odd[i];
+                    highestoddindex = i;
+                }
+            }
+            highwithodd = a[highestoddindex];
+            while (1)
+            {
+                if (highwithodd % 2 == 1)
+                    break;
+                else
+                {
+                    highwithodd = highwithodd / 2;
+                    highmult++;
+                }
+            }
+            power = mult2 - highmult;
+            sum = a[highestoddindex] * pow(2, power);
+            for (i = 0; i < n; i++)
+            {
+                if (highestoddindex != i)
+                    sum += odd[i];
+            }
+            cout << sum << endl;
+        }
+    }
+    return 0;
+}
diff --git a/competitive_programming/dumb.cpp b/competitive_programming/dumb.cpp
new file mode 100644
index 0000000..475948a
--- /dev/null
+++ b/competitive_programming/dumb.cpp
@@ -0,0 +1,18 @@
+#include <iomanip>
+#include <iostream>
+using namespace std;
+int main()
+{
+    int t, n;
+    cin >> t;
+    float ans = 1, zero = 0;
+    while (t--)
+    {
+        cin >> n;
+        if(n != 0)
+        cout << fixed << setprecision(5) << ans << endl;
+        else
+        cout << fixed << setprecision(5) << zero << endl;
+    }
+    
+}
\ No newline at end of file
diff --git a/competitive_programming/dumb.py b/competitive_programming/dumb.py
new file mode 100644
index 0000000..eab5c45
--- /dev/null
+++ b/competitive_programming/dumb.py
@@ -0,0 +1,7 @@
+t = int(input())
+c = 1
+for i in range (t):
+    a = float(input())
+    b = float(input())
+    print(f"Case {c}: {1/(1/a - 1/b)}")
+    c += 1
diff --git a/competitive_programming/equalornotcf.cpp b/competitive_programming/equalornotcf.cpp
new file mode 100644
index 0000000..d88b26a
--- /dev/null
+++ b/competitive_programming/equalornotcf.cpp
@@ -0,0 +1,21 @@
+#include <iostream>
+using namespace std;
+int main() 
+{
+    int t;
+    cin >> t;
+    string s;
+    while (t--)
+    {
+        cin >> s;
+        if (s[0] == s[s.size() - 1])
+        {
+            cout << "YES" << endl;
+        }
+        else
+            cout << "NO" << endl;
+        
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/equalornotcf.py b/competitive_programming/equalornotcf.py
new file mode 100644
index 0000000..9714263
--- /dev/null
+++ b/competitive_programming/equalornotcf.py
@@ -0,0 +1,8 @@
+t = int(input());
+for i in range (t):
+    s = input()
+    if s[0] == s[len(s) - 1]:
+        print("YES")
+    else:
+        print("NO")
+
diff --git a/competitive_programming/finaldayatc.cpp b/competitive_programming/finaldayatc.cpp
new file mode 100644
index 0000000..00cc3bc
--- /dev/null
+++ b/competitive_programming/finaldayatc.cpp
@@ -0,0 +1,23 @@
+#include <iostream>
+#include <bits/stdc++.h>
+using namespace std;
+int main()
+{
+    int n, k, i;
+    cin >> n >> k;
+    int x, y, z, totalpoints[n], sorttotalpoints[n];
+    for ( i = 0; i < n; i++)
+    {
+        cin >> x >> y >> z;
+        totalpoints[i] = x+y+z;
+        sorttotalpoints[i] = x+y+z;
+    }
+    int asize = sizeof(sorttotalpoints) / sizeof(sorttotalpoints[0]);
+    sort(sorttotalpoints, sorttotalpoints + asize);
+    for ( i = 0; i < n; i++)
+    {
+        if(totalpoints[i] + 300 >= sorttotalpoints[n-k]) cout << "Yes" << endl;
+        else cout << "No" << endl;
+    }
+    return 0;
+}
diff --git a/competitive_programming/findarrcf.cpp b/competitive_programming/findarrcf.cpp
new file mode 100644
index 0000000..11ab961
--- /dev/null
+++ b/competitive_programming/findarrcf.cpp
@@ -0,0 +1,18 @@
+#include <iostream>
+using namespace std;
+int main() 
+{
+    int t, n;
+    cin >> t;
+    while (t--)
+    {
+        cin >> n;
+        for (int i = 0; i < n; i++)
+        {
+            cout << i + 2 << " ";
+        }
+        cout << endl;
+        
+    }
+    
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/editdistancelt.cpp b/competitive_programming/learningdp/editdistancelt.cpp
new file mode 100644
index 0000000..1022553
--- /dev/null
+++ b/competitive_programming/learningdp/editdistancelt.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#define EMPTY_VALUE -1;
+using namespace std;
+int mem[20][20];
+int ed(string &s, string &w, int i, int j)
+{
+	int ans, del, ins, change, tmp;
+	ans = del = ins = change = tmp = 0;
+	if (mem[i][j] != EMPTY_VALUE)
+		return mem[i][j];
+	else if (i == s.size())
+		ans += w.size() - s.size();
+	else if (j == w.size())
+		ans = ans;
+	else
+	{
+		if (s[i] == w[j])
+			ans = ed(s, w, i + 1, j + 1);
+		else
+		{
+			del = 1 + ed(s, w, i + 1, j);
+			change = 1 + ed(s, w, i + 1, j + 1);
+			ins = 1 + ed(s, w, i, j + 1);
+			tmp = min(ins, change);
+			ans = min(del, tmp);
+		}
+	}
+	mem[i][j] = ans;
+	return ans;
+}
+
+int main()
+{
+	string s = "horse";
+	string w = "ros";
+	for (int i = 0; i < 20; i++)
+	{
+		for (int j = 0; j < 20; j++)
+		{
+			mem[i][j] = EMPTY_VALUE;
+		}
+	}
+	cout << ed(s, w, 0, 0) << endl;
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/fibRecursive.cpp b/competitive_programming/learningdp/fibRecursive.cpp
new file mode 100644
index 0000000..a92d914
--- /dev/null
+++ b/competitive_programming/learningdp/fibRecursive.cpp
@@ -0,0 +1,15 @@
+#include <iostream>
+using namespace std;
+int way (int n);
+int main()
+{
+    int n;
+    cin >> n;
+    cout << way(n);
+}
+
+int way(int n)
+{
+    if(n==0 || n==1) return 1;
+    return way(n-1) + way(n-2);
+}
diff --git a/competitive_programming/learningdp/fibiterativedp.cpp b/competitive_programming/learningdp/fibiterativedp.cpp
new file mode 100644
index 0000000..9e47c9e
--- /dev/null
+++ b/competitive_programming/learningdp/fibiterativedp.cpp
@@ -0,0 +1,14 @@
+#include <iostream>
+using namespace std;
+int main()
+{
+    int n, i;
+    cin >> n;
+    int way[n+1];
+    way[0] = way[1] = 1;
+    for ( i = 2; i <= n; i++)
+    {
+        way[i] = way[i-1] + way[i-2];
+    }
+    cout << way[n];
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/lcs.cpp b/competitive_programming/learningdp/lcs.cpp
new file mode 100644
index 0000000..42108df
--- /dev/null
+++ b/competitive_programming/learningdp/lcs.cpp
@@ -0,0 +1,49 @@
+#include <iostream>
+#define EMPTY_VALUE -1;
+using namespace std;
+int memory[10][10];
+int lcs(int i, int j, string &s, string &w)
+{
+    if (i == s.size() || j == w.size())// here "abc" and i==3 so it is out of the string
+        return 0;
+
+    if (memory[i][j] != -1)
+    {
+        return memory[i][j];
+    }
+
+    int ans = 0;
+    if (s[i] == w[j])
+    {
+        ans = 1 + lcs(i + 1, j + 1, s, w);
+    }
+    else
+    {
+        int val1 = lcs(i + 1, j, s, w);
+        int val2 = lcs(i, j + 1, s, w);
+
+        ans = max(val1, val2);
+    }
+
+    memory[i][j] = ans; // two dimentional array why:  we will have lcs for both strings
+    return memory[i][j];
+    return s.size();
+}
+
+int main()
+{
+    string s = "hellom", w = "hmrll";
+    for (int i = 0; i < 10; i++)
+    {
+        for(int j = 0; j<10; j++)
+            memory[i][j] = EMPTY_VALUE;
+    }
+    
+    cout << lcs(0, 0, s, w) <<endl;
+    for (int i = 0; i < 10; i++)
+    {
+        for(int j = 0; j<10; j++)
+    	    cout << memory[i][j] <<" ";
+		cout << endl;
+    }
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/lis.cpp b/competitive_programming/learningdp/lis.cpp
new file mode 100644
index 0000000..4effd6f
--- /dev/null
+++ b/competitive_programming/learningdp/lis.cpp
@@ -0,0 +1,46 @@
+#include <iostream>
+using namespace std;
+
+int highestincresubseqofthatindex[7];
+int f(int x)
+{
+	int array[7] = {5, 0, 9, 2, 7, 3, 4};
+	int max = 0, incresub = 0; // if you don't initialize incresub = 0 please see what happens. it happens because in recursion it repeats again -- and every time the incresub becomes some garbage values
+	if (highestincresubseqofthatindex[x] != 0)
+		return highestincresubseqofthatindex[x];
+	else
+		{
+			highestincresubseqofthatindex[x] = 0;
+			for (int i = x + 1; i < 7; i++)
+			{
+				if (array[i] >= array[x])
+					incresub = f(i);
+					if (incresub > max)
+						max = incresub;
+			}
+
+			highestincresubseqofthatindex[x] = 1 + max;
+			return highestincresubseqofthatindex[x];
+		}
+}
+
+int main()
+{
+
+	int i, lis = 0;
+	for (i = 0; i < 7; i++)
+	{
+		highestincresubseqofthatindex[i] = 0;
+	}
+
+	for (i = 0; i < 7; i++)
+	{
+		f(i);
+	}
+
+	for (i = 0; i < 7; i++)
+	{
+		if(highestincresubseqofthatindex[i] > lis) lis = highestincresubseqofthatindex[i];	
+	}
+	cout << lis << endl;
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/lisiterative.cpp b/competitive_programming/learningdp/lisiterative.cpp
new file mode 100644
index 0000000..520038c
--- /dev/null
+++ b/competitive_programming/learningdp/lisiterative.cpp
@@ -0,0 +1,12 @@
+#include <iostream>
+using namespace std;
+int main() 
+{
+   int array[7] = {5,0,9,2,7,3,4};
+    int highestincresubseqofthatindex[7];
+    for (int i = 6 ; i >= 0; i++)
+    {
+        
+    }
+    
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/shafaetfibo.cpp b/competitive_programming/learningdp/shafaetfibo.cpp
new file mode 100644
index 0000000..c25e635
--- /dev/null
+++ b/competitive_programming/learningdp/shafaetfibo.cpp
@@ -0,0 +1,22 @@
+#define MAX_N 20
+#define EMPTY_VALUE -1
+
+int memo[MAX_N + 1];
+
+int f(int n) {
+    if (n == 0) return 0; 
+    if (n == 1) return 1;
+   
+    if (memo[n] != -1) {
+        return memo[n];
+    }
+    
+    memo[n] = f(n - 1) + f(n - 2);
+    return memo[n];
+}
+
+void init() {
+  for (int i = 0; i <= MAX_N; i++) {
+      memo[i] = EMPTY_VALUE;
+  }
+}
\ No newline at end of file
diff --git a/competitive_programming/learningdp/test.cpp b/competitive_programming/learningdp/test.cpp
new file mode 100644
index 0000000..aa4544a
--- /dev/null
+++ b/competitive_programming/learningdp/test.cpp
@@ -0,0 +1,26 @@
+#include<iostream>
+#define EMPTY_VALUE -1;
+using namespace std;
+int main() 
+{
+    int memor[20][20];
+    for (int i = 0; i < 20; i++)
+    {
+        for (int j = 0; j < 20; j++)
+        {
+			memor[i][j]  == -1;
+        }
+        
+    }
+    for (int i = 0; i < 20; i++)
+    {
+        for (int j = 0; j < 20; j++)
+        {
+			cout<<memor[i][j] <<" ";
+        }
+        cout<<endl;
+    }
+    
+}
+
+
diff --git a/competitive_programming/makeevencf.py b/competitive_programming/makeevencf.py
new file mode 100644
index 0000000..0191484
--- /dev/null
+++ b/competitive_programming/makeevencf.py
@@ -0,0 +1,15 @@
+t = int(input())
+for i in range(t):
+    n = input()
+    impossible = 0
+    for j in range(len(n)):
+        if int(n[j]) % 2 == 0:
+            impossible = 1
+    if int(n[len(n)-1]) % 2 == 0:
+        print(0)
+    elif int(n[0]) % 2 == 0:
+        print(1)
+    elif impossible == 0:
+        print(-1)
+    else:
+        print(2)
diff --git a/competitive_programming/mathematicaladditionuvcf.cpp b/competitive_programming/mathematicaladditionuvcf.cpp
new file mode 100644
index 0000000..26fa6ce
--- /dev/null
+++ b/competitive_programming/mathematicaladditionuvcf.cpp
@@ -0,0 +1,12 @@
+#include <iostream>
+using namespace std;
+int main() {
+    int t, u, v;
+    cin >> t;
+    for (int i=0; i<t; i++)
+    {
+        cin >> u;
+        cin >> v;
+        cout << -u*u << " " << 1*v*v << "\n";
+    }
+}
\ No newline at end of file
diff --git a/competitive_programming/permutecf.cpp b/competitive_programming/permutecf.cpp
new file mode 100644
index 0000000..0c758d7
--- /dev/null
+++ b/competitive_programming/permutecf.cpp
@@ -0,0 +1,61 @@
+#include <iostream>
+using namespace std;
+int main() {
+    int t, n, a, b, x, y;
+    cin >> t;
+    for (int i=0; i<t; i++)
+    {
+        cin >> n >> a >> b;
+        if ((a+b)>=n)
+        {
+           int leftarr[n/2], rightarr[n/2];
+            x=y=0;
+            //a is min of leftarr
+            //b is max of rightarr
+            leftarr[x] = a;
+            x++;
+            rightarr[y] = b;
+            y++;
+            for (int i=1; i<=n; i++)
+            {
+                if (i!=a && i!=b)
+                {
+                    if (i<a)
+                    {
+                        rightarr[y] = i;
+                        y++;
+                    }
+                    else if (i>b)
+                    {
+                        leftarr[x] = i;
+                        x++;
+                    }
+                    else
+                    {
+                        if (x < n/2)
+                        {
+                            leftarr[x] = i;
+                            x++;
+                        }   
+                        else
+                        {
+                            rightarr[y] = i;
+                            y++;
+                        }    
+                    }
+                }
+            }
+            for (i=0; i<n/2; i++)
+            {
+                cout << leftarr[i] << " ";
+            }            
+            for (i=0; i<n/2; i++)
+            {
+                cout << rightarr[i] << " ";
+            } 
+            cout << "\n";      
+        }
+        else cout << -1 << "\n";
+       
+    }
+}
\ No newline at end of file
diff --git a/competitive_programming/sockscf.cpp b/competitive_programming/sockscf.cpp
new file mode 100644
index 0000000..9049d64
--- /dev/null
+++ b/competitive_programming/sockscf.cpp
@@ -0,0 +1,17 @@
+#include <iostream>
+
+int main () {
+    int n, m;
+    std::cin >> n;
+    std::cin >> m;
+    int days=0;
+    for (int i=n; i>0; i--)
+    {        
+        days++;
+        if (days%m == 0)
+        {
+            i++; //treating i as number of socks
+        }
+    }
+    std::cout << days;
+}
diff --git a/competitive_programming/takahashi.cpp b/competitive_programming/takahashi.cpp
new file mode 100644
index 0000000..2519c50
--- /dev/null
+++ b/competitive_programming/takahashi.cpp
@@ -0,0 +1,30 @@
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    int n, x, newlyknown, i;
+    cin >> n >> x;
+    newlyknown = x;
+    int kekare[n], knownornot[n];
+    for ( i = 0; i < n; i++)
+    {
+        cin >> kekare[i];
+    }
+    for ( i = 0; i < n; i++)
+    {
+        knownornot[i] = false;
+    }
+    
+    for ( i = 0; i < n; i++)
+    {
+        newlyknown = kekare[newlyknown - 1];
+        if (knownornot[newlyknown - 1] == false)
+            knownornot[newlyknown - 1] = true;
+        else
+            break;
+    }
+    cout << i + 1 << endl;
+    
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/teamcf.cpp b/competitive_programming/teamcf.cpp
new file mode 100644
index 0000000..6028622
--- /dev/null
+++ b/competitive_programming/teamcf.cpp
@@ -0,0 +1,20 @@
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    int t;
+    cin >> t;
+    for(int i = 0 ; i < t ; i++){
+        long long math, prog;
+        cin >> math >> prog;
+        long long maxteams = (int) (math + prog) / 4;
+        if(maxteams > math)
+            cout << math << endl;
+        else if(maxteams > prog)
+            cout << prog << endl;
+        else
+            cout << maxteams << endl;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/competitive_programming/teamcf.py b/competitive_programming/teamcf.py
new file mode 100644
index 0000000..a0b9d6c
--- /dev/null
+++ b/competitive_programming/teamcf.py
@@ -0,0 +1,11 @@
+t = int(input())
+for i in range(t):
+    math = int(input())
+    prog = int(input())
+    maxteams = int((math + prog)/4)
+    if maxteams > math:
+        print(math)
+    elif maxteams > prog:
+        print(prog)
+    else:
+        print(maxteams)
\ No newline at end of file
diff --git a/competitive_programming/template.cpp b/competitive_programming/template.cpp
new file mode 100644
index 0000000..b8d5504
--- /dev/null
+++ b/competitive_programming/template.cpp
@@ -0,0 +1,15 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+    int t, i;
+    cin >> t;
+    for(i = 0 ; i < t ; i++){
+        cin >> ;
+
+    }
+    return 0;
+}
+
+
+// to ignore after decimal point--> maxteams = (int) (math + prog) / 4;
diff --git a/competitive_programming/vacationcfdp.cpp b/competitive_programming/vacationcfdp.cpp
new file mode 100644
index 0000000..3906735
--- /dev/null
+++ b/competitive_programming/vacationcfdp.cpp
@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+using namespace std;
+int days[100];
+int memory[100][3];
+
+int vac(int i, int j, int prev)
+{
+    int ans = 0;
+    if (memory[i][j] != -1)
+        return memory[i][j];
+    else if (days[i] == -1)
+        return 0;
+    else
+    {
+
+        if (j == 0)
+            memory[i][j] = min(min(1 + vac(i + 1, 0), vac(i + 1, 1)), vac(i + 1, 2));
+        if (j == 1)
+            memory[i][j] = min(1 + vac(i + 1, 0), vac(i + 1, 2));
+        if (j == 2)
+            memory[i][j] = min(1 + vac(i + 1, 0), vac(i + 1, 1));
+
+        return memory[i][j];
+    }
+}
+
+int main()
+{
+    int n, i;
+    cin >> n;
+    for (i = 0; i < 1000; i++)
+    {
+        days[i] = -1;
+        memory[i] = -1;
+    }
+
+    for (i = 0; i < n; i++)
+    {
+        cin >> days[i];
+    }
+
+    cout << min(min(vac(0, 0), vac(0, 1)) , vac(0, 2)) << endl;
+
+    return 0;
+}
diff --git a/competitive_programming/vacationcfdp1.cpp b/competitive_programming/vacationcfdp1.cpp
new file mode 100644
index 0000000..16ff364
--- /dev/null
+++ b/competitive_programming/vacationcfdp1.cpp
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+using namespace std;
+int days[100];
+int memory[100][3];
+
+int vac(int i, int j)
+{
+    int ans = 0;
+    if (memory[i][j] != -1)
+        return memory[i][j];
+    else
+    {
+
+        if (j == 0)
+            memory[i][j] = min(min(1 + vac(i + 1, 0), vac(i + 1, 1)), vac(i + 1, 2));
+        if (j == 1)
+            memory[i][j] = min(1 + vac(i + 1, 0), vac(i + 1, 2));
+        if (j == 2)
+            memory[i][j] = min(1 + vac(i + 1, 0), vac(i + 1, 1));
+        return memory[i][j];
+    }
+}
+
+int main()
+{
+    int n, i;
+    cin >> n;
+    for (i = 0; i < 100; i++)
+    {
+        days[i] = -1;
+        for (int j = 0; j < 3; j++)
+        {
+            memory[i][j] = -1;
+        }
+    }
+
+    for (i = 0; i < n; i++)
+    {
+        cin >> days[i];
+    }
+
+    cout << min(min(vac(0, 0), vac(0, 1)), vac(0, 2)) << endl;
+
+
+    return 0;
+}
diff --git a/competitive_programming/vacationcfdp2.cpp b/competitive_programming/vacationcfdp2.cpp
new file mode 100644
index 0000000..2fe4a04
--- /dev/null
+++ b/competitive_programming/vacationcfdp2.cpp
@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+using namespace std;
+int days[100];
+int memory[100][3];
+
+int vac(int index, int prev)
+{
+    int ans = 0, tmp = 0;
+	if (memory[index] != -1) 
+		return memory[index];
+    else if (days[index] == -1)
+        return 0;
+    else
+    {
+        if (prev != 0)
+        {
+            if (index == 1)
+                ans = min(1 + vac(index + 1, 0), vac(index + 1, 1));
+            if (index == 2)
+                ans = min(1 + vac(index + 1, 0), vac(index + 1, 2));
+            if (index == 3)
+            {
+                tmp = min(1 + vac(index + 1, 0), vac(index + 1, 1));
+                ans = min(tmp, vac(index + 1, 2));
+            }
+        }
+        else ans = 1 + vac(index + 1, 0);
+		memory[index] = ans;
+        return ans;
+    }
+    
+}
+
+int main()
+{
+    int n, i;
+    cin >> n;
+    for (i = 0; i < 1000; i++)
+    {
+        days[i] = -1;
+		memory[i] = -1;
+    }
+
+    for (i = 0; i < n; i++)
+    {
+        cin >> days[i];
+    }
+
+    cout << vac(0, 0);
+	for (i = 0; i < n; i++)
+    {
+        cout << days[i] << endl;
+    }
+    return 0;
+}