题目地址：http://acm.nyist.net/JudgeOnline/problem.php?pid=248

思路：刚开始用DP 写写费了，看了别人的解题报告才知道用贪心也可以解决，有时间再用DP写写

AC代码：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <climits>
#include <cmath>
#include <cctype>

const int inf = 0x7f7f7f7f;//2139062143
typedef long long ll;
using namespace std;

struct node
{
    int price;
    int num;
};

bool cmp(node a,node b)
{
    return a.price < b.price;
}

int main()
{
    int t;
    int k,e,n;
    scanf("%d",&t);
    node a[110];
    while(t--)
    {
        scanf("%d%d%d",&k,&e,&n);
        int loc,price;
        for(int i=0; i<n; i++)
        {
            scanf("%d%d%d",&loc,&a[i].num,&price);
            a[i].price = (e - loc) + price;
        }
        sort(a,a+n,cmp);
        int sum = 0;
        for(int i=0; i<n; i++)
        {
            if(a[i].num >= k)
            {
                sum += k * a[i].price;
                break;
            }
            else
            {
                k -= a[i].num;
                sum += a[i].price * a[i].num;
            }
        }
        printf("%d\n",sum);
    }
    return 0;
}