Moving Tables
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 19290 Accepted Submission(s): 6585
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)
//思路：贪心算法，区间覆盖
1.区间覆盖
AC代码：
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
struct node
{
int x,y;
}a[210];
int sum[210];
int main()
{
int i,j,n,m,t,max;
scanf("%d",&m);
while(m--)
{
scanf("%d",&n);
memset(sum,0,sizeof(sum));
for(i=0;i<n;i++)
{
scanf("%d %d",&a[i].x,&a[i].y);
a[i].x=(a[i].x+1)/2;
a[i].y=(a[i].y+1)/2;
if(a[i].x>a[i].y)//桌子可能从大房间号移到小房间号
{
t=a[i].x;
a[i].x=a[i].y;
a[i].y=t;
}
for(j=a[i].x;j<=a[i].y;j++)//覆盖区间
sum[j]++;
}
sort(sum,sum+210);
printf("%d\n",sum[209]*10);
}
return 0;
}
注意：
/*1 3
4 5
是20分钟
1 4
5 6
是10分钟*/