【杭电oj1051】Wooden Sticks

Love The Way You Lie 2022-09-25 03:29 8阅读 0赞

# Wooden Sticks #

**Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)  
Total Submission(s): 18623 Accepted Submission(s): 7614**

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) ][Asia 2001_ Taejon _South Korea_]

Recommend

We have carefully selected several similar problems for you: [1050][] [1045][] [1053][] [1789][] [1003][]

先对长度进行排序，因为长度大小顺序确定了，所以只需要比较重量，把某个重量递增的序列标记，记录总够查找的次数，就是所求。

#include<cstdio>
    #include<iostream>
    #include<cstring>
    #include<algorithm>
    using namespace std;
    const int N = 5005;
    struct node {
    	int len,wei;
    } s[N];
    bool vis[N];
    bool cmp(node A,node B) {
    	if(A.len==B.len)
    		return A.wei<B.wei;
    	return A.len<B.len;
    }
    int main() {
    	int T,n;
    	scanf("%d",&T);
    	while(T--) {
    		scanf("%d",&n);
    		for(int i=0; i<n; i++) {
    			scanf("%d%d",&s[i].len,&s[i].wei);
    		}
    		sort(s,s+n,cmp);
    		int ans=0,cnt,flag;
    		memset(vis,false,sizeof(vis));
    		for(int i=0; i<n; i++) {
    			if(vis[i])
    				continue;
    			else {
    				vis[i]=true;
    				cnt=s[i].wei;
    				for(int j=i+1; j<n; j++) {
    					if(s[j].wei>=cnt&&!vis[j]) {	//for条件没写全，wa了一次。 
    						cnt=s[j].wei;		//此处j写成了i哇了一次，基本功不够扎实啊 
    						vis[j]=true;
    					}
    				}
    			}
    			ans++;
    		}
    		printf("%d\n",ans);
    	}
    	return 0;
    }

[题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1051][http_acm.hdu.edu.cn_showproblem.php_pid_1051]

[Asia 2001_ Taejon _South Korea_]: http://acm.hdu.edu.cn/search.php?field=problem&key=Asia+2001%2C+Taejon+%28South+Korea%29&source=1&searchmode=source
[1050]: http://acm.hdu.edu.cn/showproblem.php?pid=1050
[1045]: http://acm.hdu.edu.cn/showproblem.php?pid=1045
[1053]: http://acm.hdu.edu.cn/showproblem.php?pid=1053
[1789]: http://acm.hdu.edu.cn/showproblem.php?pid=1789
[1003]: http://acm.hdu.edu.cn/showproblem.php?pid=1003
[http_acm.hdu.edu.cn_showproblem.php_pid_1051]: http://acm.hdu.edu.cn/showproblem.php?pid=1051