Wooden Sticks

梦里梦外; 2021-06-24 13:58 254阅读 0赞

题目连接：[http://acm.hust.edu.cn/vjudge/contest/view.action?cid=40692\#problem/E][http_acm.hust.edu.cn_vjudge_contest_view.action_cid_40692_problem_E]

描述

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).

输入

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.

输出

The output should contain the minimum setup time in minutes, one per line.

样例输入

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

样例输出

2
    1
    3

#include<stdio.h>
    #include<string.h>
    #include<algorithm>
    using namespace std;
    struct wood
    {
        int l,w,v;
    }a[10000];
    bool cmp(wood x,wood y)
    {
        if(x.l!=y.l)
        return x.l < y.l;
        return x.w < y.w;
    }
    
    int main()
    {
        int t,n,m,i,j,sum;
        scanf("%d",&t);
        while(t--)
        {
            sum=0;
            scanf("%d",&n);
            memset(a,0,sizeof(a));
            for(i=0;i<n;i++)
            {
                scanf("%d %d",&a[i].l,&a[i].w);
    
            }
            sort(a,a+n,cmp);
            for(i=0;i<n;i++)
            {
                if(a[i].v) continue;
                int d=a[i].w;
                sum++;
                for(j=i;j<n;j++)
                {
                    if(a[j].w >= d && !a[j].v)
                    {
                        d=a[j].w;
                        a[j].v=1;
                    }
                }
            }
            printf("%d\n",sum);
    
        }
        return 0;
    }

[http_acm.hust.edu.cn_vjudge_contest_view.action_cid_40692_problem_E]: http://acm.hust.edu.cn/vjudge/contest/view.action?cid=40692#problem/E