Compilare: main.cpp: In function 'int main()': main.cpp:35:11: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses] if(!c[i]) ^ main.cpp:31:87: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin),freopen("biconex.out","w",stdout),scanf("%d%d",&n,&m); ^ main.cpp:31:87: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:31:87: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:33:64: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&i,&u),g[i].push_back(u),g[u].push_back(i); ^