Compilare: user.cpp: In function ‘int main()’: user.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<a.size(); i++) ^ user.cpp:64:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[i].size(); k++) ^ user.cpp:88:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[i].size(); k++) ^ user.cpp:17:35: 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:18:37: 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:20:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:23:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ user.cpp:29:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&dest); ^ user.cpp:96:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&k); ^