ZOJ Problem Set - 1025 Wooden Sticks

ZOJ Problem Set - 1025

Wooden Sticks

Time Limit: 2 Seconds
Memory Limit: 65536 KB

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

多少个递增子序列就多少分钟

AC代码：

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<string.h>
using namespace std;
struct Wood{
int w,l;
};
bool cmp(Wood a,Wood b)
{
if(a.w!=b.w)
{
return a.w<=b.w;
}
else
{
return a.l<=b.l;
}
}
int main()
{
int cas;
cin>>cas;
while(cas--)
{
int n;
Wood wood[10001];
cin>>n;
for(int i=0;i<n;i++)
{
cin>>wood[i].l>>wood[i].w;
}
sort(wood,wood+n,cmp);
int minuts=0;
bool *flag=new bool
;
memset(flag,0,sizeof(flag));
for(int i=0;i<n;i++)
{
if(flag[i])continue;
flag[i]=true;
minuts++;
int t=i;
for(int j=i+1;j<n;j++)
{
if(wood[t].w<=wood[j].w&&wood[t].l<=wood[j].l&&!flag[j])
{
t=j;
flag[j]=true;
}
}
}
cout<<minuts<<endl;
}
}