hdu 1051 Wooden Sticks

 

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 9578    Accepted Submission(s): 3935

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

 

213

 

题目大意：

     工厂加工一批木棍，加工所用的设备调整一次需要一分钟，

只要后面的木棍的长度和重量大于等于前面的木棍，设备就不用调整。

设备第一次启动的时候需要一分钟。木棍的顺序可以调整，

依次输入木棍的数量，长度和重量，求加工完这些木棍所需的最短时间。

思路：

     先将数据按重量进行排序，同时把重量相同的按长度进行排序。

然后每处理一个木头，就向后搜索，查找所有可以符合题意的木头。

并将已处理的木头进行标记，避免重复查找。

 

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;struct pp{int x;int y;int flag;}data[5001];int cmp(pp a,pp b){    if(a.x!=b.x)     return a.x<b.x;    else     return a.y<b.y;}int main(){    int t,count,n,tmp;  scanf("%d",&t);  while(t--)  {      scanf("%d",&n);    for(int i=0;i<n;i++)    {        scanf("%d%d",&data[i].x,&data[i].y);        data[i].flag=0;    }  sort(data,data+n,cmp);  count=0;  int i,j;for(i=0;i<n;i++){    if(data[i].flag==1) continue;    count++;tmp=i;    for(j=i+1;j<n;j++)    {      if(data[j].flag==0&&data[j].x>=data[tmp].x&&data[j].y>=data[tmp].y)        {            data[j].flag=1;            tmp=j;        }    }}cout<<count<<endl;  }   return  0;}