hdu-1051

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 12197    Accepted Submission(s): 5055

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
  
  


  
  


  
  

   题目分析：
  
  

   这道题目大概意思是给你一组数据，表示棍子的长和重，对棍子进行组装，当且仅当后者的长度跟重量大于前者的时候时间不用改变，否则的话时间加一分钟。
  
  

   用的是贪心，先对长度进行排序，当长度相同时对重量进行排序。
  
  

   采用数组进行标记。
  
  

   代码如下：
  
  

   #include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
struct keneng{
  int l;
  int w;
}s[7000];
bool cmp(keneng a,keneng b){    //排序 

   	if(a.l<b.l)

   	   return true;

   	else if(a.l>b.l)              //bool函数的返回值只能是true 

   	   return false;

   	else

   	   return a.w<b.w;
}
int main(){

   	int i,j,k,t;

   	int mark[10000];         //对算过的进行标记 

   	int N;

   	int T;

   	scanf("%d",&N);

   	while(N--){

   		scanf("%d",&T);

   		for(i=0;i<T;i++)

   		   scanf("%d %d",&s[i].l,&s[i].w);

   		sort(s,s+T,cmp);

   		memset(mark,0,sizeof(mark));

   	 int ans=0;

   	 int time=0;

   	 while(ans!=T){

   	 
   	for(i=0;i<T;i++)

   	 
   	 {

   	 
   	 
   	if(!mark[i]){

   	 
   	 
   		k=i;

   	 
   	 
   		time++;

   	 
   	 
   		break;

   	 
   	 
   	}

   	 
   	 }

   	 
   	 for(i=0;i<T;i++){

   	 
   	 
   	if(!mark[i]&&s[i].l>=s[k].l&&s[i].w>=s[k].w){

   	 
   	 
   		ans++;

   	 
   	 
   		mark[i]=1;

   	 
   	 
   		k=i;

   	 
   	 
   	}

   	 
   	 }

   	 }

   	 printf("%d\n",time);

   	}

   	return 0;
}