bitprac

Bit Manipulation/prac/uniTrip.cpp

@@ -0,0 +1,81 @@
+/*
+To find a unique number in an array where all numbers except one , are present thrice.
+
+1  001
+3  110
+2  010
+3  110
+4  100
+2  010
+1  001
+1  001
+3  110
+2  010
+
+
+array -> (int size 64) -> 64 bits array
+
+0 1 2
+3 6 4
+
+modulo by 3 gives
+0 0 1
+
+it gives
+
+4 in binary form is 100
+
+position of accourding to binary representation fill the array
+ for 0 position of array we have to check which element have setbit in 0 pos
+ only 1 has set bit in 0 position and it occurs 3 times
+
+ same for position 1 -> 6  for 2 -> 4
+
+ all which have triplets will be multiple of 3
+
+
+
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+bool getBit(int n, int pos)
+{
+    return (n & (1 << pos)) != 0; //if not = zero we have 1 in that pos
+}
+
+int setBit(int n, int pos)
+{
+    return (n | (1 << pos));
+}
+
+int uniTrip(int a[], int n)
+{
+    int result = 0;
+
+    for (int i = 0; i < 64; i++) //array of 64 bits (to cover all bits)
+    {
+        int sum = 0;
+        for (int j = 0; j < n; j++) //traverse the array
+        {
+            if (getBit(a[j], i)) //arr[j]'s ith bit is set or not
+            {
+                sum++;
+            }
+        }
+        if (sum % 3 != 0) //element which is not in triplet
+        {
+            result = setBit(result, i);
+        }
+    }
+    return result;
+}
+
+int main()
+{
+    int arr[] = {1, 3, 2, 3, 4, 2, 1, 1, 3, 2};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    cout << uniTrip(arr, n) << endl;
+    return 0;
+}

Bit Manipulation/prac/unique.cpp

@@ -0,0 +1,24 @@
+/*
+To find unique number in an array where all numbers except one, are present twice
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int uni(int a[], int n)
+{
+    int Xor = a[0];
+    for (int i = 1; i < n; i++) //getting xor of all numbers
+    {
+        Xor = Xor ^ a[i];
+    }
+    return Xor;
+}
+
+int main()
+{
+    int arr[] = {2, 4, 6, 3, 4, 6, 2};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    cout << uni(arr, n) << endl;
+    return 0;
+}