代码

#include<cstdio>
using namespace std;
 int plus(int a, int b){long long l=-int(1e9)<<1,r=int(1e9)<<1;//左边界和右边界
int c;
     while(r-l>1){c=(l+r)>>1;//二分的步骤啦
         if(c-b<a)l=c;
         else if(c-b>a)r=c;
             else return c;
     }if(l!=r)return r;
 }

评测结果