# 1582. Special Positions in a Binary Matrix
from typing import List
"""
given an 'm n' binary matrix 'mat', return the number of special positions
in 'mat'. a position '(i, j)' is called special if 'mat[i][j] == 1' and all
other elements in a row and column are 0
"""
class Solution:
def numSpecial(self, mat: List[List[int]]) -> int:
col_idx = [0] * len(mat)
row_sum = [0] * len(mat)
col_sum = [0] * len(mat[0])
for r, row in enumerate(mat):
for c, col in enumerate(mat[r]):
if col:
row_sum[r] += 1
col_sum[c] += 1
col_idx[r] = c
cnt = 0
for i, j in enumerate(row_sum):
if j == 1 and col_sum[col_idx[i]] == 1:
cnt += 1
return cnt
if __name__ == "__main__":
obj = Solution()
print(obj.numSpecial(mat=[[1, 0, 0], [0, 0, 1], [1, 0, 0]]))
print(obj.numSpecial(mat=[[1, 0, 0], [0, 1, 0], [0, 0, 1]]))
