题目链接：delete

题面：

Delete

4
1 3 1 2 
1

3

Hint
if WLD deletes a 3, the numbers remain is [1,1,2],he‘ll get 2 different numbers.
if WLD deletes a 2, the numbers remain is [1,1,3],he‘ll get 2 different numbers.
if WLD deletes a 1, the numbers remain is [1,2,3],he‘ll get 3 different numbers.
 

解题：

利用set计数即可。

代码：

#include <iostream>
#include <cmath> 
#include <set>
using namespace std;
int main()
{
	int n,k,tmp,ans;
	while(scanf("%d",&n)!=EOF)
	{
		set <int> store;
		for(int i=1;i<=n;i++)
		{
			scanf("%d",&tmp);
			store.insert(tmp);
		}
		scanf("%d",&k);
		if(n==store.size())
		{
			ans=n-k;//刚好，就直接减 
		}
		else
		{
			tmp=n-store.size();//可以不减少的前提下，提供的最大数量 
			if(tmp>=k)//够减，，数量不变 
			ans=store.size();
			else      //不够减，减去多余的后，再减种类数 
			ans=store.size()-(k-tmp);
		}
		printf("%d\n",ans);
	}
	return 0;
}

HDU 5210 DELETE

原文：http://blog.csdn.net/david_jett/article/details/46368499