Moving Tables---（贪心）

Problem Description

The famous ACM (Advanced Computer Maker) Company has rented a floor of a building whose shape is in the following figure.The floor has 200 rooms each on the north side and south side along the corridor. Recently the Company made a plan to reform its system. The reform includes moving a lot of tables between rooms. Because the corridor is narrow and all the tables are big, only one table can pass through the corridor. Some plan is needed to make the moving efficient. The manager figured out the following plan: Moving a table from a room to another room can be done within 10 minutes. When moving a table from room i to room j, the part of the corridor between the front of room i and the front of room j is used. So, during each 10 minutes, several moving between two rooms not sharing the same part of the corridor will be done simultaneously. To make it clear the manager illustrated the possible cases and impossible cases of simultaneous moving.For each room, at most one table will be either moved in or moved out. Now, the manager seeks out a method to minimize the time to move all the tables. Your job is to write a program to solve the manager’s problem.

 

Input

The input consists of T test cases. The number of test cases ) (T is given in the first line of the input. Each test case begins with a line containing an integer N , 1<=N<=200 , that represents the number of tables to move. Each of the following N lines contains two positive integers s and t, representing that a table is to move from room number s to room number t (each room number appears at most once in the N lines). From the N+3-rd line, the remaining test cases are listed in the same manner as above.

 

Output

The output should contain the minimum time in minutes to complete the moving, one per line.

 

Sample Input

3 
4 
10 20 
30 40 
50 60 
70 80 
2 
1 3 
2 200 
3 
10 100 
20 80 
30 50 

 

Sample Output

10
20
30

 

Source

Asia 2001, Taejon (South Korea)

题意：一条走廊，现在要移动桌子，从a房间移动到b房间，有交叉的地方不能同时移，即走廊的宽度只能容纳一个桌子。
分析：首先将左右的房间进行压缩，如1-2，压缩成1，即相对的房间变成了一个房间。然后一条一条的扫，经过的房间就加上1.最后求出经过房间的最大次数。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define INF 0x3f3f3f3f
const int maxn = 200+10;
int corridor[maxn];
int T;
int ans=-INF;

int main(){
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    cin>>T;
    while(T--){
        memset(corridor,0,sizeof(corridor));
        int n;
        int s,t;
        cin>>n;
        for( int i=0; i<n; i++ ){
            cin>>s>>t;
            if(s>t) swap(s,t);
            s=(s+1)/2;
            t=(t+1)/2;
            for( int j=s; j<=t; j++ ){
                corridor[j]++;
            }
        }
        ans=-INF;
        for(int i=0; i<=200; i++ ){
            ans=max(ans,corridor[i]);
        }
        cout<<ans*10<<endl;
    }
    return 0;
}