Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 9937    Accepted Submission(s): 4081

Problem Description

There is a pile of n wooden sticks. The length and weight of each stick are known in advance. The sticks are to be processed by a woodworking machine in one by one fashion. It needs some time, called setup time, for the machine to prepare processing a stick. The setup times are associated with cleaning operations and changing tools and shapes in the machine. The setup times of the woodworking machine are given as follows: (a) The setup time for the first wooden stick is 1 minute. (b) Right after processing a stick of length l and weight w , the machine will need no setup time for a stick of length l' and weight w' if l<=l' and w<=w'. Otherwise, it will need 1 minute for setup. You are to find the minimum setup time to process a given pile of n wooden sticks. For example, if you have five sticks whose pairs of length and weight are (4,9), (5,2), (2,1), (3,5), and (1,4), then the minimum setup time should be 2 minutes since there is a sequence of pairs (1,4), (3,5), (4,9), (2,1), (5,2).

Input

The input consists of T test cases. The number of test cases (T) is given in the first line of the input file. Each test case consists of two lines: The first line has an integer n , 1<=n<=5000, that represents the number of wooden sticks in the test case, and the second line contains n 2 positive integers l1, w1, l2, w2, ..., ln, wn, each of magnitude at most 10000 , where li and wi are the length and weight of the i th wooden stick, respectively. The 2n integers are delimited by one or more spaces.

Output

The output should contain the minimum setup time in minutes, one per line.

Sample Input

3

5

4 9 5 2 2 1 3 5 1 4

3

2 2 1 1 2 2

3

1 3 2 2 3 1

Sample Output

2 1 3

Source

Asia 2001, Taejon (South Korea)

采用的是，常规的方法。。。。

先进行排序，人选一个作为第一优先级...

比如以第一个聚类...以重量作为依据排序..

2 1

5 2

1 4

3 5

4 9

序列排好了...然后那样每次拿掉一条递增的序列，并统计即可！

代码：

 1 #include<cstdio>
 2 #include<vector>
 3 #include<algorithm>
 4 #include<iostream>
 5 using namespace std;
 6 typedef struct
 7 {
 8     int we;
 9     int le;
10     int tag;
11 }go;
12 int cmp(go const  a, go const b)
13 { 
14     /*升序*/
15     if(a.le==b.le)
16     {
17         if(a.we<b.we)    return 1;
18         else     return 0;
19     }
20     if(a.le<b.le)    return 1;
21     else return 0;
22 }
23 int main()
24 {
25     int t,n,cnt;
26     vector<go>st;
27     go tem;
28     scanf("%d",&t);
29     while(t--)
30     {
31         st.clear();
32         scanf("%d",&n);
33         while(n--)
34         {
35             scanf("%d%d",&tem.le,&tem.we);
36             tem.tag=true;
37             st.push_back(tem);
38         }
39        sort(st.begin(),st.end(),cmp);
40        vector<go>::iterator it,tem;
41        cnt=0;
42        bool falg;
43        while(!st.empty())
44        {
45            falg=true;
46        for(it=st.begin(); it!=st.end();it++)
47          {
48            if(it->tag&&falg) tem=it;
49           if(it->tag&&tem->we<=it->we)
50            {
51                tem=it;
52                it->tag=false;
53                falg=false;
54            }
55          }
56          if(!falg) cnt++;
57          else break;
58        }
59        printf("%dn",cnt);
60     }
61     return 0;
62 }