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.
 

用set先放所有的不重复的，如果k小于等于n-是s.size()就输出s.size(),否则就输出s.size()-(n-k)

代码：

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <set>
using namespace std;

set<int > s;

int main(){
    int n;
    while(scanf("%d", &n) == 1){
        s.clear();
        int a;
        for(int i = 0;i < n; ++ i){
            scanf("%d", &a);
            s.insert(a);
        }
        int k;
        scanf("%d", &k);
        int temp = n - s.size();
        if(k <= temp){
            cout << s.size()<<endl;
        }
        else{
            cout << (s.size()-(k-temp))<<endl;
        }
    }
    return 0;
} 

Hdoj 5210 Delete 【水】

原文：http://blog.csdn.net/shengweisong/article/details/45293445