第五题网红，暴力解了，为什么一直50%，而且不是超时和数组越界的问题，不解 import sys import queue ''' input:3 3 1 2 2 1 2 3 output:1 ''' if __name__ == '__main__':     N = int(sys.stdin.readline().strip())     M = int(sys.stdin.readline().strip())     line = sys.stdin.readline().strip().split()     relationshape = []     Nmatrix = [[0 for i in range(N)] for j in range(N)]     for i in range(M):         tmp = (int(line[2*i]),int(line[2*i+1]))         relationshape.append(tmp)     for i in relationshape:         tmpi = i[0]-1         tmpj = i[1]-1         Nmatrix[tmpi][tmpj] = 1         for i in range(N):             if(Nmatrix[i][tmpi]==1):                 Nmatrix[i][tmpj]=1 #     print(Nmatrix)     result = 0     for i in range(N):         count = 0         for j in range(N):             if(Nmatrix[j][i]==1 and j!=i):                 count+=1         if(count == N-1):             result += 1     print(result)