Compilare: user.cpp: In function ‘int main()’: user.cpp:26:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[i].size(); ++j) ~~^~~~~~~~~~~~~ user.cpp:28:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[i].size(); ++j) { ~~^~~~~~~~~~~~~ user.cpp:30:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < G[i].size() && G[i][j - 1].first == G[i][j].first) { ~~^~~~~~~~~~~~~ user.cpp:40:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < G[i].size(); ++j) { ~~^~~~~~~~~~~~~ user.cpp:12:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("restrictii.in", "r", stdin); ^ user.cpp:13:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("restrictii.out", "w", stdout); ^ user.cpp:16:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &val); ^ 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", &x, &y, &z); ^