Compilare: main.cpp: In function 'int main()': main.cpp:66:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<ans.size(); i++) ~^~~~~~~~~~~ main.cpp:58:28: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized] extra[x]++; extra[y]++; ~~~~~~~^ main.cpp:58:16: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized] extra[x]++; extra[y]++; ~~~~~~~^