题目

Description

There is a war and it doesn’t look very promising for your country. Now it’s time to act.
You have a commando squad at your disposal and planning an ambush on an important enemy camp located nearby.
You have N soldiers in your squad.
In your master-plan, every single soldier has a unique responsibility and you don’t want any of your soldier to know the plan for other soldiers so that everyone can focus on his task only.
In order to enforce this, you brief every individual soldier about his tasks separately and just before sending him to the battlefield.
You know that every single soldier needs a certain amount of time to execute his job.
You also know very clearly how much time you need to brief every single soldier.
Being anxious to finish the total operation as soon as possible, you need to find an order of briefing your soldiers that will minimize the time necessary for all the soldiers to complete their tasks.
You may assume that, no soldier has a plan that depends on the tasks of his fellows.
In other words, once a soldier begins a task, he can finish it without the necessity of pausing in between.

Input

There will be multiple test cases in the input file. Every test case starts with an integer N (1 ≤
N ≤ 1000), denoting the number of soldiers. Each of the following N lines describe a soldier with two
integers B (1 ≤ B ≤ 10000) & J (1 ≤ J ≤ 10000). B seconds are needed to brief the soldier while
completing his job needs J seconds. The end of input will be denoted by a case with N = 0. This case
should not be processed.

Output

For each test case, print a line in the format, ‘Case X: Y ’, where X is the case number & Y is the
total number of seconds counted from the start of your first briefing till the completion of all jobs.

Sample Input

3
2 5
3 2
2 1
3
3 3
4 4
5 5
0

Sample Output

Case 1: 8
Case 2: 15

题解

有 安排工作时间 和 工作时间
求最短的工作时间

要想时间最短就要尽可能让大家的工作时间重合
显然应该先让工作时间最长的尽早投入到工作中

代码

/*
By:OhYee
Github:OhYee
Blog:http://www.oyohyee.com/
Email:oyohyee@oyohyee.com

かしこいかわいい？
エリーチカ！
要写出来Хорошо的代码哦~
*/
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <iostream>
#include <map>
#include <set>
#include <list>
#include <queue>
#include <stack>
#include <string>
#include <vector>
#include <bitset>
#include <functional>

using namespace std;

const int maxn = 1005;
struct Node {
    int a,b;
    bool operator < (const Node &rhs)const {
        if(b == rhs.b)
            return a < rhs.a;
        return b > rhs.b;
    }
};

int kase = 1;
Node s[maxn];


bool Do() {
    int n;
    cin >> n;
    if(n == 0)
        return false;

    for(int i = 0;i < n;i++)
        cin >> s[i].a >> s[i].b;

    sort(s,s + n);

    int end = 0;
    int time = 0;
    for(int i = 0;i < n;i++) {
        time += s[i].a;
        end = max(end,time + s[i].b);
    }
    cout <<"Case "<<kase++<<": "<< end << endl;
    return true;
}

int main() {
    while(Do());
    return 0;
}