Compilare: user.cpp: In function ‘int main()’: user.cpp:29:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < L[i].size(); ++j) ^ user.cpp:38:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < G[L[i][j]].size(); ++k) ^ user.cpp:10:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gminmax.in", "r", stdin); ^ user.cpp:11:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gminmax.out", "w", stdout); ^ user.cpp:14:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:17:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &xx, &yy); ^