Main.cc:82:5: error: redefinition of ‘long long int ct’ int ct=0; ^~ Main.cc:64:5: note: ‘long long int ct’ previously defined here int ct=0; ^~ Main.cc: In function ‘void dfs(long long int, long long int)’: Main.cc:86:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(dep==E.size()){ ~~~^~~~~~~~~~