Compilare: main.cpp: In function 'int main()': main.cpp:40:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (x < f[i - 1].size() && y < f[i].size()) { ~~^~~~~~~~~~~~~~~~~ main.cpp:40:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (x < f[i - 1].size() && y < f[i].size()) { ~~^~~~~~~~~~~~~ main.cpp:44:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = y; j < f[i].size(); ++ j) q += f[i][j]; ~~^~~~~~~~~~~~~ main.cpp:53:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; x < f[i - 1].size(); ++ x) aux += f[i - 1][x]; ~~^~~~~~~~~~~~~~~~~ main.cpp:54:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; y < f[i].size(); ++ y) aux += f[i][y]; ~~^~~~~~~~~~~~~