poj1456（贪心）

A supermarket has a set Prod of products on sale. It earns a profit px for each product x∈Prod sold by a deadline dx that is measured as an integral number of time units starting from the moment the sale begins. Each product takes precisely one unit of time for being sold. A selling schedule is an ordered subset of products Sell ≤ Prod such that the selling of each product x∈Sell, according to the ordering of Sell, completes before the deadline dx or just when dx expires. The profit of the selling schedule is Profit(Sell)=Σ _x∈Sellpx. An optimal selling schedule is a schedule with a maximum profit.
For example, consider the products Prod={a,b,c,d} with (pa,da)=(50,2), (pb,db)=(10,1), (pc,dc)=(20,2), and (pd,dd)=(30,1). The possible selling schedules are listed in table 1. For instance, the schedule Sell={d,a} shows that the selling of product d starts at time 0 and ends at time 1, while the selling of product a starts at time 1 and ends at time 2. Each of these products is sold by its deadline. Sell is the optimal schedule and its profit is 80.

Write a program that reads sets of products from an input text file and computes the profit of an optimal selling schedule for each set of products.

Input

A set of products starts with an integer 0 <= n <= 10000, which is the number of products in the set, and continues with n pairs pi di of integers, 1 <= pi <= 10000 and 1 <= di <= 10000, that designate the profit and the selling deadline of the i-th product. White spaces can occur freely in input. Input data terminate with an end of file and are guaranteed correct.

Output

For each set of products, the program prints on the standard output the profit of an optimal selling schedule for the set. Each result is printed from the beginning of a separate line.

Sample Input

4  50 2  10 1   20 2   30 17  20 1   2 1   10 3  100 2   8 2   5 20  50 10

Sample Output

80185

/*此题的贪心策略和我之前做的hdu1789一样,按照最大利益贪心。按照最大利益的顺序，最后期限填空用掉一天标记一天那么保证用掉的每一天都是最大的（详情见代码或者博主hdu1789完全一样的贪心只是输出不一样）*/

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct node{    int p, t;    bool operator < (const node & a) const{        if(p == a.p) return t < a.t;        else            return p > a.p;    }}pp[10000+100];int vis[10000+100];int main(){    int n;    while(scanf("%d", &n) != EOF){        long long ans = 0;        memset(vis, 0, sizeof(vis));        for(int i = 0; i < n; i++){            scanf("%d%d", &pp[i].p, &pp[i].t);        }        sort(pp, pp+n);        long long sum = 0;        for(int i = 0; i < n; i++){            int flag = 0;            for(int j = pp[i].t; j >= 1; j--){    //注意>=1博主写的时候习惯性的把最小时间当做了0然后wa的怀疑人生                if(!vis[j]){                    vis[j] = 1;                    sum += pp[i].p;                    break;                }            }        }        printf("%lld\n", sum);    }    return 0;}