hdoj 1051 Wooden Sticks（LIS变形）

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 15695    Accepted Submission(s): 6446

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
dp和贪心都行！
 dp:
   
#include<stdio.h>#include<string.h>#include<algorithm>using namespace std; #define  N  999999struct node{    int l;    int w;}a[N];bool cmp(node  a,node  b){    if(a.l ==b.l )    return  a.w<b.w;    return  a.l <b.l; } int dp[N];int main(){    int t,n;    scanf("%d",&t);    while(t--)    {        int i,j,k,temp;        scanf("%d",&n);        for(i=0;i<n;i++)        {            scanf("%d%d",&a[i].l ,&a[i].w );            dp[i]=1;        }        sort(a,a+n,cmp);        for(i=0;i<n;i++)          for(j=0;j<i;j++)           {               if(a[i].w<a[j].w&&dp[i]<dp[j]+1)               dp[i]=dp[j]+1;           }           int max=-1;           for(i=0;i<n;i++)            {                if(max<dp[i])                max=dp[i];            }            printf("%d\n",max);    }    return 0;  }

 
贪心：
  
#include<stdio.h>#include<string.h>#include<algorithm>using namespace std; #define  N  999999struct node{int l;int w;}a[N];bool cmp(node  a,node  b){if(a.l ==b.l )return  a.w<b.w;return  a.l <b.l; } int dp[N];int main(){int t,n;scanf("%d",&t);while(t--){int i,j,k,temp;scanf("%d",&n);for(i=0;i<n;i++){scanf("%d%d",&a[i].l ,&a[i].w );}sort(a,a+n,cmp);int time=0;for(i=0;i<n;i++){if(a[i].w !=0)temp=a[i].w ;elsecontinue;  for(j=i+1;j<n;j++)   {      if(temp<=a[j].w&&a[j].w !=0)  {  temp=a[j].w ;  a[j].w =0;  }    }   a[i].w =0;    time++;    }printf("%d\n",time );}return 0;  }