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Copy pathqueens-attack-2.py
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queens-attack-2.py
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#!/bin/python3
import sys
from collections import defaultdict
from math import fabs
def check_diag(queen, obst):
if queen[1] == obst[1]:
return 0
check = (queen[0] - obst[0])/(queen[1] - obst[1])
if fabs(check) == 1.0:
return int(check)
else:
return 0
def queensAttack(n, k, r_q, c_q, obstacles):
queen = [r_q, c_q]
res = 0
obst_by_row = list(filter(lambda x: x[0] == r_q, obstacles))
obst_by_col = list(filter(lambda x: x[1] == c_q, obstacles))
obst_by_plus_diag = list(filter(lambda x: check_diag(queen, x) == 1, obstacles))
obst_by_neg_diag = list(filter(lambda x: check_diag(queen, x) == -1, obstacles))
if not obst_by_col:
res += n-1
else:
obst_higher = list(filter(lambda x: x[0] > r_q, obst_by_col))
if obst_higher:
min_higher = min(obst_higher, key = lambda x: x[0])[0]
else:
min_higher = n+1
obst_lower = list(filter(lambda x: x[0] < r_q, obst_by_col))
if obst_lower:
max_lower = max(obst_lower, key = lambda x: x[0])[0]
else:
max_lower = 0
#print("high = {} low = {}".format(min_higher, max_lower))
res += min_higher - max_lower - 2
if not obst_by_row:
res += n-1
else:
obst_higher = list(filter(lambda x: x[1] > c_q, obst_by_row))
if obst_higher:
min_higher = min(obst_higher, key = lambda x: x[1])[1]
else:
min_higher = n+1
obst_lower = list(filter(lambda x: x[1] < c_q, obst_by_row))
if obst_lower:
max_lower = max(obst_lower, key = lambda x: x[1])[1]
else:
max_lower = 0
#print("high = {} low = {}".format(min_higher, max_lower))
res += min_higher - max_lower - 2
# diagonals
if not obst_by_plus_diag:
res += n-1 - abs(r_q - c_q)
#res += min(n - c_q, n - r_q) + min(c_q - 1, r_q - 1) # = n-1 + min(-c_q, -r_q) + min(c_q, r_q)
#print("res = {}".format(res))
else:
obst_higher = list(filter(lambda x: x[0] > r_q, obst_by_plus_diag))
if obst_higher:
min_higher = min(obst_higher, key = lambda x: x[0])[0]
else:
min_higher = n+1
obst_lower = list(filter(lambda x: x[0] < r_q, obst_by_plus_diag))
if obst_lower:
max_lower = max(obst_lower, key = lambda x: x[0])[0]
else:
max_lower = 0
#print("high = {} low = {}".format(min_higher, max_lower))
res += min_higher - max_lower - 2 - abs(r_q - c_q)
if not obst_by_neg_diag:
#print("n - c_q + r_q = {} - {} + {}".format(n, c_q, r_q))
#res += n-1 - abs(n - c_q + r_q)
#print("res = {}".format(res))
#res += min(n - c_q, r_q - 1) + min(c_q - 1, n - r_q)
# 2 variants:
# res += n - c_q + n - r_q = 2n - c_q - r_q
# res += r_q - 1 + c_q - 1 = r_q + c_q - 2
res += min(n - c_q, r_q - 1)
res += min(c_q - 1, n - r_q)
else:
obst_higher = list(filter(lambda x: x[0] > r_q, obst_by_neg_diag))
if obst_higher:
min_higher = min(obst_higher, key = lambda x: x[0])[1]
else:
min_higher = n+1
obst_lower = list(filter(lambda x: x[0] < r_q, obst_by_neg_diag))
if obst_lower:
max_lower = max(obst_lower, key = lambda x: x[0])[1]
else:
max_lower = 0
print("high = {} low = {}".format(min_higher, max_lower))
print("r_q = {} c_q = {}".format(r_q, c_q))
#res += min_higher - max_lower - 2 - abs(n - c_q + r_q)
if max_lower != 0:
res += max_lower - c_q - 1
if min_higher != n+1:
res += c_q - min_higher - 1
return res
# naive
def queensAttack_naive(n, k, r_q, c_q, obstacles):
obst_by_row = list(filter(lambda x: x[0] == r_q, obstacles))
obst_by_col = list(filter(lambda x: x[1] == c_q, obstacles))
obs_dict = gen_obs_dict(obstacles)
res = 0
if not obst_by_col:
res += n-1
else:
for row_ind in range(r_q+1, n+1):
#if not [row_ind, c_q] in obstacles:
key = str(row_ind) + "-" + str(c_q)
if obs_dict[key] != -1:
res += 1
else:
break
for row_ind in range(r_q-1, 0, -1):
#if not [row_ind, c_q] in obstacles:
key = str(row_ind) + "-" + str(c_q)
if obs_dict[key] != -1:
res += 1
else:
break
if not obst_by_row:
res += n-1
else:
for col_ind in range(c_q+1, n+1):
#if not [r_q, col_ind] in obstacles:
key = str(r_q) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
else:
break
for col_ind in range(c_q-1, 0, -1):
#if not [r_q, col_ind] in obstacles:
key = str(r_q) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
else:
break
row_ind, col_ind = r_q+1, c_q+1
while col_ind != 0 and row_ind != 0 and col_ind != n+1 and row_ind != n+1:
#if not [row_ind, col_ind] in obstacles:
key = str(row_ind) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
row_ind += 1
col_ind += 1
else:
break
row_ind, col_ind = r_q-1, c_q+1
while col_ind != 0 and row_ind != 0 and col_ind != n+1 and row_ind != n+1:
#if not [row_ind, col_ind] in obstacles:
key = str(row_ind) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
row_ind -= 1
col_ind += 1
else:
break
row_ind, col_ind = r_q+1, c_q-1
while col_ind != 0 and row_ind != 0 and col_ind != n+1 and row_ind != n+1:
#if not [row_ind, col_ind] in obstacles:
key = str(row_ind) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
row_ind += 1
col_ind -= 1
else:
break
row_ind, col_ind = r_q-1, c_q-1
while col_ind != 0 and row_ind != 0 and col_ind != n+1 and row_ind != n+1:
#if not [row_ind, col_ind] in obstacles:
key = str(row_ind) + "-" + str(col_ind)
if obs_dict[key] != -1:
res += 1
row_ind -= 1
col_ind -= 1
else:
break
return res
def gen_obs_dict(obstacles):
dict_out = defaultdict(int)
for obs in obstacles:
row, col = obs[0], obs[1]
key = str(row) + "-" + str(col)
dict_out[key] = -1
return dict_out
if __name__ == "__main__":
n, k = [int(x) for x in input().strip().split(' ')]
r_q, c_q = [int(x) for x in input().strip().split(' ')]
obstacles = []
for obstacles_i in range(k):
obstacles_t = [int(obstacles_temp) for obstacles_temp in input().strip().split(' ')]
obstacles.append(obstacles_t)
result = queensAttack_naive(n, k, r_q, c_q, obstacles)
print(result)