代码

int binary_search(const unsigned *a, int n, unsigned x){
	int l=0,r=n-1;
	while(l<r){
		int mid=l+(r-l)/2;
		if (a[mid]==x)
			return mid;
		if (a[mid]>x)
			r=mid-1;
		else l=mid+1;
	}
	return l;
}

评测结果