Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:15:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:59:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[j]].size(); ++k) ^ user.cpp:75:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[nr]].size(); ++k) ^ user.cpp:95:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[j]].size(); ++k) ^ user.cpp:107:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[j]].size(); ++k) ^ user.cpp:120:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[nr]].size(); ++k) ^ user.cpp:132:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[nr]].size(); ++k) ^ user.cpp:152:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[j]].size(); ++k) ^ user.cpp:164:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[j]].size(); ++k) ^ user.cpp:177:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[nr]].size(); ++k) ^ user.cpp:189:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<g[v[nr]].size(); ++k) ^ user.cpp:24:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.in","r",stdin); ^ user.cpp:25:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.out","w",stdout); ^ user.cpp:28:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:31:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v1[i]); ^ user.cpp:35:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v2[i]); ^