Compilare: user.cpp: In function ‘int main()’: user.cpp:94:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[0].size(); ++i) ^ user.cpp:107:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < sol.size() && !sameForest; ++k) ^ user.cpp:156:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j <finalSol[i].size(); ++j) ^ user.cpp:52:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.in","r",stdin); ^ user.cpp:53:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.out","w",stdout); ^ user.cpp: In function ‘int getint()’: user.cpp:28:55: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if (++ptr>=maxb) fread(buf,maxb,1,stdin),ptr=0; ^ user.cpp:31:55: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if (++ptr>=maxb) fread(buf,maxb,1,stdin),ptr=0; ^