HOJ---10814 Wooden Sticks[线性DP-求最少不递增子序列+结构体排序]

Wooden Sticks

Time Limit: 1000ms, Special Time Limit:2500ms, Memory Limit:32768KB

Total submit users: 145, Accepted users: 127

Problem 10814 : No special judgement

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

Problem Source

Asia 2001, Taejon (South Korea)

 

 

 

 

 

注意下当两棵树high相等的时候要对weight进行排序。

code:

#include <iostream>   
#include <iomanip>   
#include <fstream>   
#include <sstream>   
#include <algorithm>   
#include <string>   
#include <set>   
#include <utility>   
#include <queue>   
#include <stack>   
#include <list>   
#include <vector>   
#include <cstdio>   
#include <cstdlib>   
#include <cstring>   
#include <cmath>   
#include <ctime>   
#include <ctype.h> 
using namespace std;

struct Tree
{
    int high,weight;
}tree[5005];

int operator <(const Tree &a,const Tree &b)
{
    if(a.high==b.high)
        return a.weight>b.weight;
    else
        return a.high>b.high;
}

int main()
{
    int t;
    int i,j;
    int n;
    int max;
    int dp[5200];
    while(~scanf("%d",&t))
    {
        while(t--)
        {
            max=-1;
            scanf("%d",&n);
            for(i=0;i<n;i++)
                scanf("%d%d",&tree[i].high,&tree[i].weight);
            sort(tree,tree+n);
            for(i=0;i<n;i++)
                dp[i]=1;
            for(i=1;i<n;i++)
                for(j=i-1;j>=0;j--)
                    if((tree[i].weight>tree[j].weight)&&dp[i]<dp[j]+1)
                        dp[i]=dp[j]+1;
            for(i=0;i<n;i++)
                if(dp[i]>max)
                    max=dp[i];
            printf("%d\n",max);
        }
    }
    return 0;
}