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
Output for the Sample Input
2
1
3
#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
struct Stick
{
int l;
int w;
}stick[5005];
bool cmp(const Stick a,const Stick b)
{
if(a.l == b.l)
return a.w < b.w;
return a.l < b.l;
}
bool vis[5005];
int n ,t;
int main()
{
while(~scanf("%d",&t))
{
while(t--)
{
scanf("%d",&n);
for(int i = 0; i < n; i++)
{
scanf("%d%d",&stick[i].l,&stick[i].w);
}
sort(stick,stick + n ,cmp);
memset(vis,0,sizeof(vis));
int num = 0;
int l,w;
int cnt = 0,tt = 0;
while(tt < n)
{
vis[num] = 1;
tt++;
l = stick[num].l;
w = stick[num].w;
bool flag = false;
for(int i = num + 1; i < n;i++)
{
if(!vis[i]&&stick[i].l >= l && stick[i].w >= w)
{
w = stick[i].w;
l = stick[i].l;
vis[i] = 1;
tt++;
}
else if(!vis[i]&&!flag)
{
flag = true;
num = i;
}
}
cnt++;
}
printf("%d
",cnt);
}
}
return 0;
}