杭电acm Wooden Sticks

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 23191    Accepted Submission(s): 9411

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

 

//贪心问题，先处理最长最重的木头以便一台机器可以处理尽可能多的木头，

/** * date:2017.11.15 * author:孟小德 * function:杭电acm1051 * */import java.util.*;public class acm1051{    public static void main(String[] args)    {        Scanner input = new Scanner(System.in);        int num = input.nextInt();        int[] result = new int[num];        for (int j=0;j<num;j++)        {            int wood_num = input.nextInt();            wood[] array = new wood[wood_num];            for (int i=0;i<wood_num;i++)            {                int len = input.nextInt();                int weight = input.nextInt();                array[i] = new wood(len,weight);            }            sort(array);            int use_num = 0;            result[j] = 0;            wood temp = new wood();            while (use_num < wood_num)            {                for (int i=0;i<wood_num;i++)                {   //寻找未处理木头中最长最重的一根                    if(array[i].use == false)                    {                        temp = array[i];                        break;                    }                }                for (int i=0;i<wood_num;i++)                {// 寻找可以被同时处理的木头                    if (array[i].use == false && array[i].len <= temp.len &&                    array[i].weight <= temp.weight)                    {                        array[i].use = true;                        use_num++;                        temp = array[i];                    }                }                result[j]++;            }        }        for (int i=0;i<result.length;i++)        {            System.out.println(result[i]);        }    }    //按长度排序，长度相同则按重量排序    public static void sort(wood[] array)    {        boolean flag = true;        wood temp = new wood();        for (int i = 0;i<array.length && flag;i++)        {            flag = false;            for (int j = 0;j<array.length-i-1;j++)            {                if (array[j].len < array[j+1].len)                {                    temp.len = array[j].len;                    temp.weight = array[j].weight;                    array[j].len = array[j+1].len;                    array[j].weight = array[j+1].weight;                    array[j+1].len = temp.len;                    array[j+1].weight = temp.weight;                    flag = true;                }                else if (array[j].len == array[j+1].len)                {                    if (array[j].weight < array[j+1].weight)                    {                        temp.len = array[j].len;                        temp.weight = array[j].weight;                        array[j].len = array[j+1].len;                        array[j].weight = array[j+1].weight;                        array[j+1].len = temp.len;                        array[j+1].weight = temp.weight;                        flag = true;                    }                }            }        }    }}class wood{    public int len;    public int weight;    public boolean use = false;    public wood()    {    }    public wood(int len,int weight)    {        this.len = len;        this.weight = weight;    }}