Compilare: main.cpp: In function 'void dfs1(int)': main.cpp:19:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < G[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfs2(int)': main.cpp:44:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < G[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfs3(int)': main.cpp:55:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < T[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:102:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < mc.size() ; i ++) ~~^~~~~~~~~~~ main.cpp:111:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < mch.size() ; i ++) ~~^~~~~~~~~~~~ main.cpp:116:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < mch.size() ; i ++) ~~^~~~~~~~~~~~ main.cpp:119:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = i + 1 ; j < mch.size() ; j ++) ~~^~~~~~~~~~~~ main.cpp:122:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = j + 1 ; k < mch.size() ; k ++) ~~^~~~~~~~~~~~ main.cpp:81:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("petrica.in" , "r" , stdin); ^ main.cpp:82:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("petrica.out" , "w" , stdout); ^ main.cpp:84:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ main.cpp:86:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &p[i]); ^