Compilare: main.cpp: In function 'void dfs(int)': main.cpp:76:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G1[node].size(); i++) ~^~~~~~~~~~~~~~~~ main.cpp: In function 'void compute_max_dist()': main.cpp:118:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G3[node].size(); i++) ~^~~~~~~~~~~~~~~~ main.cpp: In function 'void solve()': main.cpp:149:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<max_dist[D].size();i++) ~^~~~~~~~~~~~~~~~~~~ main.cpp:152:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G2[node].size();j++) ~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:195:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<G1[i].size(); j++) ~^~~~~~~~~~~~~ main.cpp:211:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1; j<G2[i].size(); j++) ~^~~~~~~~~~~~~ main.cpp:219:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<v.size(); j++) ~^~~~~~~~~ main.cpp:231:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<G2[i].size(); j++) ~^~~~~~~~~~~~~ main.cpp:250:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<sol.size(); i++) ~^~~~~~~~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:19:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^