代码

int binary_search(const unsigned *a, int n, unsigned x)
{
	int l=1,r=n;
        while (l^r)
        {int mid=(l>>1)+(r>>1)+(l&r&1);
         if (a[mid]==x) return mid;
         ((a[mid]>x)?(r=mid-1):(l=mid+1));
        }
}

评测结果