Compilare: user.cpp: In function ‘int main()’: user.cpp:102:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[a[last].second].size(); j++) ^ user.cpp:56:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("matrice2.in", "r", stdin); ^ user.cpp:57:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("matrice2.out", "w", stdout); ^ user.cpp:59:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &q); ^ user.cpp:63:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:86:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &x1, &y1, &x2, &y2); ^