Main.cc: In function ‘void dfs2(long long int, long long int)’: Main.cc:11:23: error: break statement not within loop or switch if(tim>=90000000) break; ^~~~~ Main.cc:24:10: warning: unused variable ‘res’ [-Wunused-variable] bool res=0; ^~~ Main.cc: In function ‘void slv()’: Main.cc:64:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&n,&m); ~~~~~^~~~~~~~~~~~~~~~~~