Compilare: user.cpp: In function ‘int main()’: user.cpp:51:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < lst[i].size(); j ++ ) ^ user.cpp:56:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0, k = 0; j < lst[i].size(); j ++ ) { ^ user.cpp:57:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( ; k < lst[i].size() && lst[i][j].second + 1 - lst[i][k].second >= 0; k ++ ) ^ user.cpp:63:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < lst[i].size(); j ++ ) ^