poj 2392 Space Elevator

Space Elevator

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 8306 Accepted: 3932

Description

The cows are going to space! They plan to achieve orbit by building a sort of space elevator: a giant tower of blocks. They have K (1 <= K <= 400) different types of blocks with which to build the tower. Each block of type i has height h_i (1 <= h_i <= 100) and is available in quantity c_i (1 <= c_i <= 10). Due to possible damage caused by cosmic rays, no part of a block of type i can exceed a maximum altitude a_i (1 <= a_i <= 40000). 

Help the cows build the tallest space elevator possible by stacking blocks on top of each other according to the rules.

Input

* Line 1: A single integer, K 

* Lines 2..K+1: Each line contains three space-separated integers: h_i, a_i, and c_i. Line i+1 describes block type i.

Output

* Line 1: A single integer H, the maximum height of a tower that can be built

Sample Input

37 40 35 23 82 52 6

Sample Output

48

Hint

OUTPUT DETAILS: 

From the bottom: 3 blocks of type 2, below 3 of type 1, below 6 of type 3. Stacking 4 blocks of type 2 and 3 of type 1 is not legal, since the top of the last type 1 block would exceed height 40.

Source

USACO 2005 March Gold

多重背包，先按高度从小到大排序

#include <iostream>#include <cstring>#include <cstdio>#include <algorithm>using namespace std;bool dp[40005];struct node{    int h,a,c;}t[405];int cmp(node a,node b){    return a.a<b.a;}int main(){    int n;    while(scanf("%d",&n)!=EOF){        for(int i=0;i<n;i++)scanf("%d%d%d",&t[i].h,&t[i].a,&t[i].c);        memset(dp,0,sizeof(dp));        dp[0]=1;        sort(t,t+n,cmp);        for(int i=0;i<n;i++){            for(int j=0;j<t[i].c;j++){                for(int k=t[i].a;k>=t[i].h;k--)                    dp[k]|=dp[k-t[i].h];            }        }        for(int i=t[n-1].a;i>=0;i--){            if(dp[i]){                printf("%d\n",i);                break;            }        }    }    return 0;}