HDU1051 Wooden Sticks

                                                        Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 9125    Accepted Submission(s): 3729

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)

#include<stdio.h> #include<algorithm> using namespace std; struct node   //存储棍子属性，长，重，是否访问   {     int l;     int w;     int v; }str[5002]; bool cmp(node a,node b)   //按长度、重量从小到大排序 {     if(a.l==b.l)         return a.w<b.w;     return a.l<b.l; } int main() {     int t,n;     int tim;     int i,j;     scanf("%d",&t);     while(t--)     {         tim=0;         scanf("%d",&n);         for(i=0;i<n;i++)         {             scanf("%d%d",&str[i].l,&str[i].w);             str[i].v=0;         }         sort(str,str+n,cmp);   //排序         int l,w;         for(i=0;i<n;i++)     //选取第i根木棒（排序后）为加工时的第一根木棒         {             if(str[i].v==0)             {                 l=str[i].l;                 w=str[i].w;                 str[i].v=1;                 tim++;             }             for(j=i+1;j<n;j++)             {                 if(str[j].v==0&&str[j].l>=l&&str[j].w>=w)                 {                     l=str[j].l;                     w=str[j].w;                     str[j].v=1;                 }             }         }         printf("%d\n",tim);     }     return 0; }