代码

int binary_search(const unsigned *a, int n, unsigned x)
{
	int l=0,r=n-1,mid=0;
while(l<r)
{
mid=l+(r-l>>1);
if(a[mid]==x)return mid;
(a[mid]<x)?l=mid+1:r=mid-1;
}
return l;
}

评测结果