Compilare: main.cpp: In function 'int main()': main.cpp:44:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 2; i <= euler.size(); i++) ~~^~~~~~~~~~~~~~~ main.cpp:46:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < euler.size(); i++) { ~~^~~~~~~~~~~~~~ main.cpp:57:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; (1 << i) <= euler.size(); i++) { ~~~~~~~~~^~~~~~~~~~~~~~~ main.cpp:58:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j + (1 << i) - 1 < euler.size(); j++) ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~ main.cpp:63:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < g[i].size(); j++) { ~~^~~~~~~~~~~~~ main.cpp:65:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j < g[i].size() - 1) { ~~^~~~~~~~~~~~~~~~~