Compilare: main.cpp: In function 'bool okk(int)': main.cpp:34:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v2.size();j++) ~^~~~~~~~~~ main.cpp: In function 'void backtracking(int)': main.cpp:55:6: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k==v1.size()+1) ~^~~~~~~~~~~~~ main.cpp:57:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=ans[k-1]+1;i<=v1.size();i++) ~^~~~~~~~~~~