Compilare: user.cpp: In function ‘int main()’: user.cpp:29:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<=v[i].size()-1;k++) ^ user.cpp:41:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<=v[0].size()-1;i++) ^ user.cpp:7:37: 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:8:39: 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:9:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:15:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^