【HDU - 3466 】Proud Merchants(dp,背包问题,巧妙排序)
題干:
Recently, iSea went to an ancient country. For such a long time, it was the most wealthy and powerful kingdom in the world. As a result, the people in this country are still very proud even if their nation hasn’t been so wealthy any more.?
The merchants were the most typical, each of them only sold exactly one item, the price was Pi, but they would refuse to make a trade with you if your money were less than Qi, and iSea evaluated every item a value Vi.?
If he had M units of money, what’s the maximum value iSea could get??
?
Input
There are several test cases in the input.?
Each test case begin with two integers N, M (1 ≤ N ≤ 500, 1 ≤ M ≤ 5000), indicating the items’ number and the initial money.?
Then N lines follow, each line contains three numbers Pi, Qi and Vi (1 ≤ Pi ≤ Qi ≤ 100, 1 ≤ Vi ≤ 1000), their meaning is in the description.?
The input terminates by end of file marker.?
?
Output
For each test case, output one integer, indicating maximum value iSea could get.?
?
Sample Input
2 10 10 15 10 5 10 5 3 10 5 10 5 3 5 6 2 7 3Sample Output
5 11題目大意:
給你一些錢 m ,然后在這個國家買東西, 共有 n 件物品,每件物品有? 價格 P??? 價值 V??? 還有一個很特別的屬性 Q,?Q 指 你如過想買這件物品 你的手中至少有這錢Q?。 雖然你只要花費?錢P ,但你的手中至少有錢Q,如果不足Q ,不能買。問給你錢M ,列出N件物品,最多能獲得多少價值的東西。。。。
解題報告:
? ? 先排序,然后跑一邊0-1背包即可。這個排序很巧妙啊
AC代碼:
#include<bits/stdc++.h> using namespace std; struct Node {int p,q,v; } node[500 + 5]; int dp[5000 + 5]; bool cmp(const Node & a,const Node & b) {return a.q-a.p<b.q-b.p;//b.q+a.p>b.p+a.q } int main() {int n,m;while(cin>>n>>m) {for(int i = 1; i<=n; i++) {scanf("%d%d%d",&node[i].p,&node[i].q,&node[i].v);}memset(dp,0,sizeof(dp));sort(node+1,node+n+1,cmp);for(int i = 1; i<=n; i++) {for(int j = m;j >=max(node[i].q,node[i].p); j--) {dp[j] = max(dp[j],dp[j-node[i].p ] + node[i].v);}}printf("%d\n",dp[m]);}return 0; }?
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