Compilare: main.cpp: In function 'void solve()': main.cpp:50:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; j < v[i].size(); j++) ~~^~~~~~~~~~~~~ main.cpp:54:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j < v[i].size()){ ~~^~~~~~~~~~~~~ main.cpp:55:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; j < v[i].size() - 1; j++) ~~^~~~~~~~~~~~~~~~~