Compilare: main.cpp: In function 'int main()': main.cpp:69:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=1; j<=gr[i].size(); j++){ ~^~~~~~~~~~~~~~ main.cpp:73:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<gr[i].size(); j++){ ~^~~~~~~~~~~~~ main.cpp:78:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<gr[i].size(); j++){ ~^~~~~~~~~~~~~ main.cpp:81:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int l=1; l<=gr[i].size(); l++){ ~^~~~~~~~~~~~~~ main.cpp:107:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=1; j<=gr[i].size(); j++){ ~^~~~~~~~~~~~~~ main.cpp:34:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("input", "r", stdin);freopen("output", "w", stdout); ^ main.cpp:34:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("input", "r", stdin);freopen("output", "w", stdout); ^