HDU 1051:Wooden Sticks

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 16247    Accepted Submission(s): 6668

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)

 

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迷失在幽谷中的鸟儿，独自飞翔在这偌大的天地间，却不知自己该飞往何方……

#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
struct mood
{
    int w;
    int l;
} d[5005];
bool cmp(mood a,mood b)
{
    if(a.l==b.l)
        return a.w<b.w;
    return a.l<b.l;
}
int k[5005];
int main()
{
    int n;
    cin>>n;
    while(n--)
    {
        int m;
        cin>>m;
        for(int i=0; i<m; i++)
            cin>>d[i].l>>d[i].w;
        sort(d,d+m,cmp);
        memset(k,-1,sizeof(k));
        int flag=0;
        for(int i=0; i<m; i++)
            for(int j=0; j<=m; j++)
                if(d[i].w>=k[j])
                {
                    k[j]=d[i].w;
                    if(j+1>flag)flag=j+1;
                    break;
                }
        cout<<flag<<endl;
    }
    return 0;
}