用二分图染色判定+二分答案做法的也可能wa1，同样是答案为0时需要特判！ ```cpp while(l<=r){ int mid=l+r>>1; if(check(mid))r=mid-1; else l=mid+1; } if(r==-1)cout<<0;//不要忘特判QAQ else cout<<r; ``` by A_Little_BadBoy @ 2024-03-28 09:23:19