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.


题意：
从n个数中删k个数，求剩下的数中最多有多少个不同的数
代码：
#include<cstdio>
#include<set>
using namespace std;

int a[105];

int main()
{
    set<int> st;
    int n;
    while(scanf("%d",&n)==1)
    {
        st.clear();
        for(int i=0;i<n;i++)
        {
            scanf("%d",&a[i]);
            st.insert(a[i]);
        }
        int cnt=n-st.size();
        int k;
        scanf("%d",&k);
        if(k<=cnt)
            printf("%d\n",st.size());
        else
            printf("%d\n",st.size()-k+cnt);
    }
    return 0;
}