HDU 1050 Moving tables

Moving Tables

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 16607    Accepted Submission(s): 5687

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

102030

 

题目大意：有四百间房间分别在走廊的两边，一边是房号都是奇数的，一边是房号都是偶数的，从一个房间向另一个房间移桌子，走廊只能容纳一张桌子的空间，移动一张桌子需要10min，共有T次测试，每次测试有n组数据（代表有n张桌子要移动），每组数据包括s和t（代表从s号房间向t号房间移桌子），求每次移动n张桌子所用的最少时间。

分析：贪心算法。依题意，我们所求的就是n组是[s,t]重叠的次数，将走廊边上序号，想象成一个数组，每次有桌子经过值就加一，最后找数组中最大的值a，所得最少时间即为10*a,注意，s可能小于t。