Compilare: user.cpp: In function ‘int main()’: user.cpp:30:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<A[j].size(); k++) ^ user.cpp:36:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<A[0].size(); i++) ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen("hamilton.in", "r", stdin); ^ user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hamilton.out", "w", stdout); ^ user.cpp:11:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:17:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &co); ^