Assignments---（贪心）

Assignments

Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2038    Accepted Submission(s): 1013

Problem Description

In a factory, there are N workers to finish two types of tasks (A and B). Each type has N tasks. Each task of type A needs xi time to finish, and each task of type B needs yj time to finish, now, you, as the boss of the factory, need to make an assignment, which makes sure that every worker could get two tasks, one in type A and one in type B, and, what's more, every worker should have task to work with and every task has to be assigned. However, you need to pay extra money to workers who work over the standard working hours, according to the company's rule. The calculation method is described as follow: if someone’ working hour t is more than the standard working hour T, you should pay t-T to him. As a thrifty boss, you want know the minimum total of overtime pay.

 

Input

There are multiple test cases, in each test case there are 3 lines. First line there are two positive Integers, N (N<=1000) and T (T<=1000), indicating N workers, N task-A and N task-B, standard working hour T. Each of the next two lines has N positive Integers; the first line indicates the needed time for task A1, A2…An (Ai<=1000), and the second line is for B1, B2…Bn (Bi<=1000).

 

Output

For each test case output the minimum Overtime wages by an integer in one line.

 

Sample Input

2 5 4 2 3 5

 

Sample Output

4

 

Source

2010 Asia Regional Harbin

 题意：（转）有两个长度为N（N<=1000）的序列A和B，把两个序列中的共2N个数分为N组，使得每组中的两个数分别来自A和B，每组的分数等于max(0,组内两数之和-t)，问所有组的分数之和的最小值。

分析：贪心策略，将A，B排序，A中最大的和B中最小的一组，即将A升序排序，将B降序排序，这样便是最优解。。。

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn =1e3+10;
int a[maxn],b[maxn];
bool cmp(const int a,const int b){
    return a>b;
}
int main(){
    int n,t;
    while(~scanf("%d%d",&n,&t)){
        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,cmp);
        int ans=0;
        for(int i=0; i<n; i++ ){
            if(a[i]+b[i]>t) ans+=a[i]+b[i]-t;
        }
        cout<<ans<<endl;
    }
    return 0;
}