Compilare: user.cpp: In function ‘int main()’: user.cpp:26:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<a.size(); i++) ^ user.cpp:56:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[i].size(); k++) ^ user.cpp:80:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[i].size(); k++) ^ user.cpp:16:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bridge.in","r",stdin); ^ user.cpp:17:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bridge.out","w",stdout); ^ user.cpp:19:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:22:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ user.cpp:28:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&dest); ^ user.cpp:88:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&k); ^