POJ1065

Wooden Sticks Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 14948   Accepted: 6133 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 <cstdio>

#include <algorithm>

#include <cstring>



using namespace std;



typedef struct

{

    int l;

    int w;

}STICK;



int t,n;

STICK stick[5010];

int rlt;

int dp[5010];



bool cmp(STICK s1, STICK s2)

{

    bool flag=false;



    if(s1.l<s2.l)

    {

        flag=true;

    }

    else if(s1.l==s2.l)

    {

        if(s1.w<s2.w)

        {

            flag=true;

        }

    }



    return flag;

}



int main()

{

    scanf("%d",&t);

    while(t--)

    {

        scanf("%d",&n);

        for(int i=0; i<n; i++)

        {

            scanf("%d %d",&stick[i].l,&stick[i].w);

        }



        sort(stick,stick+n,cmp);



        memset(dp,0,sizeof(dp));

        dp[0]=1;

        for(int i=1; i<n; i++)

        {

            int max=1;

            for(int j=0; j<=i; j++)

            {

                if(stick[i].w<stick[j].w && dp[j]+1>max)

                {

                    max=dp[j]+1;

                }

                dp[i]=max;

            }

        }

        rlt=-1;

        for(int i=0; i<n; i++)

        {

            if(rlt<dp[i])

            {

                rlt=dp[i];

            }

        }

        printf("%d\n",rlt);



    }

    return 0;

}