Compilare: main.cpp: In function 'int main()': main.cpp:38:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[y].size(); i++) ~~^~~~~~~~~~~~~ main.cpp:13:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.in", "r", stdin); ^ main.cpp:14:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.out", "w", stdout); ^ main.cpp:17:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:19:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^