Compilare: main.cpp: In function 'int main()': main.cpp:44:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<Sol[i].size(); ++j) printf("%d ", Sol[i][j]); ~^~~~~~~~~~~~~~ main.cpp:17:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fof.in", "r", stdin); ^ main.cpp:18:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fof.out", "w", stdout); ^ main.cpp:19:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ main.cpp:23:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^