UVa 11729 Commando War

链接：

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=2829

/*
   刘汝佳《训练指南》第一章 例题2
   UVa  11729  Commando War 
   贪心 , 用“相邻交换法”证明正确性
                      ------ by shuangde
 */
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define REP(i,n) for(int i=0; i<(n); ++i)
using namespace std;

const int MAXN = 10000;
struct node{
    int b, j;
    friend bool operator<(const node&a,const node&b){
        return a.j > b.j;
    }
}arr[MAXN];

int main(){
    int n,cas=0;;
    while(~scanf("%d",&n) && n){
        printf("Case %d: ", ++cas);
        REP(i, n) scanf("%d%d",&arr[i].b, &arr[i].j);
        sort(arr, arr+n);
        int maxx=0, tt=0;
        REP(i, n){
            tt += arr[i].b;
            if(arr[i].j + tt > maxx) 
                maxx = arr[i].j + tt;
        }
        printf("%d\n", maxx);
    }
    return 0;
}