题解 | #查找#

//二分查找，要求数组必须有序，那也就是先排序再查找
#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int a[100];
bool erfen(int n,int x)
{
	int left=0;
	int right=n-1;
	int mid;
	while(left<=right)
	{
		mid=(left+right)/2;
		if(a[mid]==x)
		{
			return true;
		}
		else if(a[mid]<x)
		{
			left=mid+1;
			
		}
		else
		{
			right=mid-1;
		}
	}
	return false;
}
int main()
{
	int n;
	int m;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		scanf("%d",&a[i]);
	}
	sort(a,a+n);
	
	scanf("%d",&m);
	
	while(m--)
	{
		int x;
		scanf("%d",&x);
		if(erfen(n,x))
		{
			printf("YES\n");
		}
		else
		printf("NO\n");
	}
	
	
	
	
	
	
	
 }