Wooden Sticks(hdu1051)

 

Wooden Sticks

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u

Submit Status Practice _

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

//第一行是代表测试数据t
每组数据第一行是一个整数 n ，代表木头的数量
然后 n 对数据 代表 木头的长度，和重量

需要一个机器处理这些木棒，机器开启的时候需要耗费一个单位的时间，如果第i+1个木棒的重量和长度都大于等于

第i个处理的木棒，那么将不会耗费时间，否则需要消耗一个单位的时间。

问最短时间

//贪心解决了

排个序，就行

#include <stdio.h>
#include <iostream>
#include <algorithm>
using namespace std;

struct Node
{
    int l,w;
}node[5005],setup[5005];

bool cmp(Node a,Node b)
{
    if (a.l==b.l)
        return a.w<b.w;
    return a.l<b.l;
}

int main()
{
    int t;
    cin>>t;
    while (t--)
    {
        int n;
        int i,j;
        cin>>n;
        for (i=0;i<n;i++)
        {
            cin>>node[i].l>>node[i].w;
        }
        sort(node,node+n,cmp);
        int ans=1;
        setup[0].l=node[0].l;
        setup[0].w=node[0].w;

        for (i=1;i<n;i++)
        {
            int ok=0;
            for (j=0;j<ans;j++)
            {
                if (setup[j].l<=node[i].l&&setup[j].w<=node[i].w)
                {
                    setup[j].l=node[i].l;
                    setup[j].w=node[i].w;
                    ok=1;
                    break;
                }
            }
            if (ok==0)
            {
                setup[ans].l=node[i].l;
                setup[ans].w=node[i].w;
                ans++;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}