HDU - 1051 Wooden Sticks-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_41760511/article/details/82019934

Wooden Sticks

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

题意：给你n根木棍的长度和重量。根据要求求出制作该木棍的最短时间。建立第一个木棍需要1分钟，如果接着制作的木棍比这个木棍的长度长，重量要重，那么接着制作的木棍不需要花费时间！依次类推，反之，则需要花费一分钟，然后让你求出制作这一批木棍花费的最少的时间是多少。

贪心ac，结构体定义木棍，长度，重量，同时定义一个f 标记。

首先按照木棍的长度进行排序，如果长度相等则重量重的放在前面。

根据建立的数组遍历比较他们的重量，如果大于标记数组跳过，否则t加1。


#include <bits/stdc++.h>
using namespace std;

struct wooden
{
    int l,w,f;
}s[5005];

bool compare(wooden a,wooden b)
{
	if(a.l==b.l)
        return a.w>b.w;
	return a.l>b.l;
}
int main()
{
    int N;
    scanf("%d",&N);
    while(N--)
    {
        int n,t=0;
        scanf("%d",&n);
        for(int i=0;i<n;i++)
        {
            scanf("%d%d",&s[i].l,&s[i].w);
            s[i].f=0;
        }
        sort(s,s+n,compare);
        int x;
        for(int i=0;i<n;i++)
        {
            if(s[i].f)
                continue;
            x=s[i].w;
            for(int j=i+1;j<n;j++)
            {
                if(s[j].f)
                    continue;
                if(x>=s[j].w)
                {
                    s[i].f=s[j].f=1;
                    x=s[j].w;
                }
            }
            s[i].f=1;
            t++;
        }
        printf("%d\n",t);
    }
    return 0;
}