洛谷 4823 [TJOI2013]拯救小矮人

题目链接-> 噔楞

题解：

贪心

按个高+臂长排序。

个矮臂长的先走，个高臂短的后走

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define N 2007
using namespace std; 
int f[N], n, flag, now, ans;
struct node{
    int x, y;
}edge[N << 1];
bool cmp(node x, node y){
    return x.x + x.y > y.x + y.y;
}
int main(){
     scanf("%d", &n);
     for(int i = 1; i <= n; i++)
         scanf("%d%d", &edge[i].x, &edge[i].y), now += edge[i].x;
     scanf("%d", &flag);
     sort(edge + 1, edge + 1 + n, cmp);
     memset(f, -1, sizeof(f));
     f[0] = now;
     for(int i = n; i >= 1; i--){
         for(int j = ans; j >= 0; j--)
             if(f[j] + edge[i].y >= flag) f[j + 1] = max(f[j + 1], f[j] - edge[i].x);
        if(f[ans + 1] >= 0) ans++;
    }
    printf("%d", ans);
    return 0;
}

一世安宁