Wooden Sticks



Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 13836    Accepted Submission(s): 5716

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)

#include <iostream>
#include<algorithm>
using namespace std;

struct ac
{
    int l,w;
    int flag;
}node[5005];

bool cmp(ac a,ac b)
{
     if(a.l<b.l)
        return true;
     else if(a.l>b.l)
         return false;
     else
       return a.w<b.w;
}

int main()
{
    int n,t,i,j,count,k;
    cin>>t;
    while(t--)
    {
        count=0;
        for(i=0;i<5005;i++)
            node[i].flag=0;
        cin>>n;
        for(i=0;i<n;i++)
        {
            cin>>node[i].l;
            cin>>node[i].w;
        }
        sort(node,node+n,cmp);
        for(i=0;i<n;i++)
        {
            if(node[i].flag==1)
                continue;
            count++;
            k=i;
            node[i].flag=1;
            for(j=i+1;j<n;j++)
            {
                if(node[j].l>=node[k].l&&node[j].w>=node[k].w&&node[j].flag==0)
                {
                    node[j].flag=1;
                    k=j;
                }

            }
        }
        cout<<count<<endl;
    }

    return 0;
}