csuoj-1722-Race

题目：

Description

Johnson and Bob are crazy motorcycle collecting enthusiasts. In order to prove their own motorcycles is the best, they issued a challenge to each other. Johnson wants to win the challenge.As a good friend of Johnson’s, you need to give advice to Johnson. Johnson and Bob each can select their best n motorcycles. And each motorcycle has a value v. There are n matches in total. Any motorcycle can be chosen optionally to participate in the match(but each motorcycle can only participate once). Each time the motorcycle with high value will win. Johnson gets the order of Bob’s motorcycles in advance. Can you help Johnson arrange the competition order of motorcycles in order to win the most of the matches?

 

Input

First line input an integer T（mean there are T cases）
In each case , first line input an integer n (mean there are n motorcycles) (0<n<=10000)
Next line input n integers (mean the value of Johnson’s n motorcycles)
Next line n integers (mean the value of Bob’s n motorcycles )

Output

Every case output an integer mean the most match can win.

Sample Input

1
5
6 4 5 1 3
8 9 3 4 7

Sample Output

2
分析：
设Johnson的数组为a,Bob的数组为b。为了尽可能赢得更多的比赛，从a数组中最大的开始匹配b数组中最大的并且小于该值的值，直至b数组中没有元素可以匹配。
代码：
#include<iostream>
#include<algorithm>
using namespace std;
int a[10000];
int b[10000];
int main(){
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        for(int i = 0;i < n;i++) cin >> a[i];
        for(int i = 0;i < n;i++) cin >> b[i];
        sort(a,a + n);
        sort(b,b + n);
        int ans = 0;
        int indexa,indexb;
        indexa = indexb = n - 1;
        while(indexb != -1){
            if(a[indexa] > b[indexb]){
                indexa--;
                indexb--;
                ans++;
            }
            else indexb--;
        }
        cout << ans << endl;
    }
    return 0;
}