Compilare: user.cpp: In function ‘int main()’: user.cpp:35:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(a[i][j][p%2].size()==k)l=p; ^ user.cpp:17:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("submatrix.in", "r", stdin); ^ user.cpp:18:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("submatrix.out", "w", stdout); ^ user.cpp:19:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ user.cpp:22:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &l); ^