(贪心算法)Wooden Sticks

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

#include
#include
#include
#include
#define MAXN 5010
using namespace std;
int sum;
struct Node{
    int l;
    int w;
}node[MAXN];
int  vis[MAXN];
bool com(const Node &p,const Node &q)
{
    if(p.l<=q.l)
        return 1;
    if(p.l<=q.l&&p.w<=q.w)
        return 1;
    if(p.l==q.l)
        return p.w<=q.w;
    else return 0;

}
int main()
{
    int cases;
    cin>>cases;
    while(cases--)
    {
        int n;
        int c=0;
        memset(vis,0,sizeof(vis));
        sum=0;
        cin>>n;
        for(int i=0;i>node[i].l>>node[i].w;
            }
        sort(node,node+n,com);
        int flag=0;
        int bs;
        for(int i=0;i