Compilare: main.cpp: In function 'void solve()': main.cpp:31:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == col.size() - 1) { ~~^~~~~~~~~~~~~~~~~ main.cpp:41:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < col.size(); i++) { ~~^~~~~~~~~~~~ main.cpp:52:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans != col.size()) { ~~~~^~~~~~~~~~~~~ main.cpp:64:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < col.size(); i++) { ~~^~~~~~~~~~~~ main.cpp:75:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < col.size(); i++) { ~~^~~~~~~~~~~~ main.cpp:86:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans != col.size()) { ~~~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:119:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < col.size(); i++) { ~~^~~~~~~~~~~~