Compilare: user.cpp: In function ‘int main()’: user.cpp:128:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmcm.in", "r", stdin); ^ user.cpp:129:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmcm.out", "w", stdout); ^ user.cpp:131:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int n, m, e; scanf("%d %d %d", &n, &m, &e); ^ user.cpp:135:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int s, t, u; scanf("%d%d%d", &s, &t, &u); ^ user.cpp: In function ‘void min_assignment(const std::vector<std::vector<int> >&, const std::vector<std::vector<int> >&)’: user.cpp:72:12: warning: ‘l’ may be used uninitialized in this function [-Wmaybe-uninitialized] int j, l; ^ user.cpp:95:11: warning: ‘w’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (h == w) { ^