# HDU ACM 1051 Wooden Sticks

340人阅读 评论(0)

## 原题描述

### 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

2
1
3

## 参考代码

#include <iostream>
#include <algorithm>
using namespace std;

struct wood
{
int l, w, flag;             // 增加flag标旗，0表示未处理，1表示已处理
}W[5001];

bool cmp(wood a,wood b)         // 长度长的放前面，如果长度一样，重量重的放前面
{
return a.l != b.l ? a.l > b.l : a.w > b.w;
}

int main()
{
int t, n, ans, min;
cin >> t;
while(t--)
{
ans = 0;
cin >> n;
for (int i = 0; i < n;i++)
{
cin >> W[i].l >> W[i].w;
W[i].flag = 0;
}
sort(W, W + n, cmp);                // 长度长的排前面，反向枚举

for (int i = 0; i < n;i++)
{
if (W[i].flag == 1)
continue;
ans++;
W[i].flag = 1;                  // 开始第一趟枚举
min = W[i].w;                   // 标记当前的木头重量
for (int j = i + 1; j < n; j++)
{
if (W[j].w <= min && W[j].flag == 0)    // 与之后的比较重量，如果重量小于前一个，那标记为已处理，并且赋值给min
{
min = W[j].w;
W[j].flag = 1;
}
}
}
cout << ans << endl;
}
}
0
0

* 以上用户言论只代表其个人观点，不代表CSDN网站的观点或立场
个人资料
• 访问：28181次
• 积分：898
• 等级：
• 排名：千里之外
• 原创：61篇
• 转载：11篇
• 译文：0篇
• 评论：7条
阅读排行
最新评论
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3154458701610565, "perplexity": 2514.051350690176}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187824899.43/warc/CC-MAIN-20171021205648-20171021225648-00351.warc.gz"}