Compilare: main.cpp: In function 'void add(int)': main.cpp:52:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[x].size(); i++) { ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:107:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < q.front().second.size(); i++) { ~~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:58:39: 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); ^ main.cpp:59:41: 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); ^ main.cpp:61:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &nrq); ^ main.cpp:64:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &mat[i][j]); ^ main.cpp:84:45: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &a, &b, &x, &y); ^