ACM刷题之HDU————Wooden Sticks

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 17181    Accepted Submission(s): 7010

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
   
   
   
   

 

一道不错的贪心题目

下面是ac代码（注意不要弄反 l 和 l'   w 和 w' 的关系）

#include<stdio.h>
#include<stdlib.h>
#include<algorithm>
using namespace std;
#define maxn  10000
int a[maxn][5];
int main()
{
    int zu,gen,n,i,j,x,temp,s,t,flags,ma;
    while(scanf("%d",&zu)!=EOF)
    {
        while(zu--)
        {   x=0;
        	flags=0;
            memset(a,0,sizeof(a));
            scanf("%d",&gen);
            n=gen;
            for(int x=0;x<gen;x++)
            {
                scanf("%d%d",&a[x][0],&a[x][1]);
            }
            gen=n;		
            //冒泡排序 
             for(i = 0; i < n; i++)
            {
                for(j = 0;  j < n-i-1; j++)
                {
                    if(a[j][0] > a[j + 1][0])
                    {
                        temp = a[j][0];
                        a[j][0] = a[j + 1][0];
                        a[j + 1][0] = temp;
                        //////
                        temp = a[j][1];
                        a[j][1] = a[j + 1][1];
                        a[j + 1][1] = temp;
                    }
                }
            }
                ////////////  排序完成 ////////////       
             for(int i=0;i<n;i++)
             {
             	if(a[i][2]==1)
             	continue;
             	else
             	x++;
				ma=a[i][1];         	
             	for(int j=1;j<n;j++)
                if(a[j][1]>=ma&&a[j][2]==0)
                {   
                    a[j][2]=1;
                    ma=a[j][1];
                }
                for(int e=1;e<n;e++)
                {
                	if(a[e][2]==0)
                	{
	                	flags=1;
	                	break;
	                }
                }
                if(flags==1)
                {
                	flags=0;
                	continue;
                }
                else
                	break;
             }             
             printf("%d\n",x);
        }
    }
}

不会结构体的我只能用多维数组来代替了，排序的时候要手动冒泡排序才行，其中a[i][0]代表长度，a[i][1]代表重量，a[i][2] 来判断是否被锯过。