HDU1051：Wooden Sticks

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

 

//嗯，加油~

 

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

int mark[5005];

struct node
{
    int a;
    int b;
} data[5005];

bool cmp(const node &a,const node &b)
{
    if(a.a>b.a)
    return true;
    if(a.a==b.a)
    {
        if(a.b>b.b)
        return true;
        else return false;
    }
    if(a.a<b.a)
    return false;
}

int main()
{
    int t,n,ans,m;
    cin>>t;
    while(t--)
    {
        cin>>n;
        memset(mark,0,sizeof(mark));
        ans=0;
        for(int i=0;i<n;i++)
        cin>>data[i].a>>data[i].b;
        sort(data,data+n,cmp);
        //for(int i=0;i<n;i++)
        //cout<<data[i].a<<" "<<data[i].b<<endl;
        for(int i=0;i<n;i++)
        {
           if(mark[i]==0)
           {
               ans++;
               m=i;
               for(int j=i+1;j<n;j++)
               {
                   if(data[m].b>=data[j].b&&mark[j]!=1)
                   {
                       mark[j]=1;
                       m=j;
                   }
               }
           }

        }
        cout<<ans<<endl;

    }
    return 0;
}