Dream City（线性DP）

描述

JAVAMAN is visiting Dream City and he sees a yard of gold coin trees. There are n trees in the yard. Let's call them tree 1, tree 2 ...and tree n. At the first day, each tree i has a_i coins on it (i=1, 2, 3...n). Surprisingly, each tree i can grow b_i new coins each day if it is not cut down. From the first day, JAVAMAN can choose to cut down one tree each day to get all the coins on it. Since he can stay in the Dream City for at most m days, he can cut down at most m trees in all and if he decides not to cut one day, he cannot cut any trees later. (In other words, he can only cut down trees for consecutive m or less days from the first day!)

Given n, m, a_i and b_i (i=1, 2, 3...n), calculate the maximum number of gold coins JAVAMAN can get.

输入

There are multiple test cases. The first line of input contains an integer T (T <= 200) indicates the number of test cases. Then T test cases follow.

Each test case contains 3 lines: The first line of each test case contains 2 positive integers n and m (0 < m <= n <= 250) separated by a space. The second line of each test case contains n positive integers separated by a space, indicating a_i. (0 < a_i <= 100, i=1, 2, 3...n) The third line of each test case also contains n positive integers separated by a space, indicating b_i. (0 < b_i <= 100, i=1, 2, 3...n)

输出

For each test case, output the result in a single line.

样例输入

2
2 1
10 10
1 1
2 2
8 10
2 3

样例输出

10
21

提示

Test case 1: JAVAMAN just cut tree 1 to get 10 gold coins at the first day.
Test case 2: JAVAMAN cut tree 1 at the first day and tree 2 at the second day to get 8 + 10 + 3 = 21 gold coins in all.

题目大意：

输入n,m分别代表n个数，和能砍m棵树，接下来n个数字ai代表第i棵树原有的金币，再接下来n个数字bi代表第i棵树每天增长的硬币。

将树按b升序排序，然后循环更新dp值即可。

#include <bits/stdc++.h>
using namespace std;
struct p
{
    int a,b;
}x[255];
int dp[255];
bool cmp(p a,p b)
{
    if(a.b!=b.b) return a.b<b.b;
    return a.a<b.a;
}
int main()
{
    ios::sync_with_stdio(false);
    int T;
    cin>>T;
    while(T--)
    {
        memset(dp,0,sizeof dp);
        int n,m;
        cin>>n>>m;
        for(int i=0;i<n;i++)
            cin>>x[i].a;
        for(int i=0;i<n;i++)
            cin>>x[i].b;
        sort(x,x+n,cmp);
        for(int i=0;i<n;i++)
            for(int j=m;j>0;j--)
                dp[j]=max(dp[j],dp[j-1]+x[i].a+x[i].b*(j-1));
        cout<<dp[m]<<'
';
    }
    return 0;
}