HDU 1051 Wooden Sticks

[align=left]Problem Description[/align]
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).

[align=left]Input[/align]
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.

[align=left]Output[/align]
The output should contain the minimum setup time in minutes, one per line.

[align=left]Sample Input[/align]

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

[align=left]Sample Output[/align]

2
1
3

//Wooden Sticks 贪心
#include <iostream>
#include<algorithm>

using namespace std;

typedef struct stick
{
int length;
int weight;
int flag;
}St;

St s[5003];

int cmp(const St &a,const St &b)
{
if(a.length!=b.length) return a.length<b.length;
else a.weight<b.weight;
}
int main()
{
int t;
int n;
cin>>t;
while(t--)
{
cin>>n;
for(int i=0;i<n;i++)
{
cin>>s[i].length>>s[i].weight;
s[i].flag=0;
}
sort(s,s+n,cmp);
int count=0;
for(int i=0;i<n;i++)
{
if(s[i].flag==1) continue;
count++;int tmp=i;
for(int j=i+1;j<n;j++)
{

if(!s[j].flag&&s[j].length>=s[tmp].length&&s[j].weight>=s[tmp].weight)
{
s[j].flag=1;
tmp=j;
}
}
}
cout<<count<<endl;
}
return 0;
}