POJ 1065 Wooden Sticks

Wooden Sticks

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 16262		Accepted: 6748

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 ( 9 , 4 ) , ( 2 , 5 ) , ( 1 , 2 ) , ( 5 , 3 ) , and ( 4 , 1 ) , then the minimum setup time should be 2 minutes since there is a sequence of pairs ( 4 , 1 ) , ( 5 , 3 ) , ( 9 , 4 ) , ( 1 , 2 ) , ( 2 , 5 ) .

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 2n 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

Taejon 2001

#include <iostream>

#include <cstring>

#include <cstdio>

#include <algorithm>

using namespace std;

struct Node

{

    int l;

    int w;

    int id;

}p[5555];

bool cmp(Node x,Node y)

{

    if(x.l!=y.l)

    {

        return x.l<y.l;

    }

    else

    {

        return x.w<y.w;

    }

}

int main()

{

    int T;

    cin>>T;

while(T--)

{

    memset(p,0,sizeof(p));

    int n;

    cin>>n;

    for(int i=0;i<n;i++)

    {

        cin>>p.l>>p.w;

        p.id=i;

    }

    sort(p,p+n,cmp);

    int dp[5555];

    for(int i=0;i<n;i++)

    {

        dp=1;

        for(int j=0;j<i;j++)

        {

            if(p.w<p[j].w)

            {

                if(dp<dp[j]+1)

                {

                    dp=dp[j]+1;

                }

            }

        }

    }

    int maxn=-1;

    for(int i=0;i<n;i++)

    {

//        cout<<p.id<<" ";

        maxn=max(maxn,dp);

    }

//    cout<<endl;

    cout<<maxn<<endl;

}

    return 0;

}