dp --- CSU 1547: Rectangle

 Rectangle

Problem's Link:   http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1547

---

 

Mean: 

给你一些宽为1或2 的木板，让你放在一个宽为二的盒子里面，问你这个盒子最短有多长。

analyse:

简单dp，一开始想错了。

Time complexity: O(n)

 

Source code: 

 

//  Memory   Time

//  1347K     0MS

//   by : crazyacking

//   2015-03-29-22.02

#include<map>

#include<queue>

#include<stack>

#include<cmath>

#include<cstdio>

#include<vector>

#include<string>

#include<cstdlib>

#include<cstring>

#include<climits>

#include<iostream>

#include<algorithm>

#define MAXN 10005

#define LL long long

using namespace std;

int Cas,n,dp[MAXN];

int main(){

    cin>>Cas;

    while(Cas--)

    {

        int cnt = 0 ,sum=0;

        scanf("%d",&n);

        int ta, tb; 

        memset(dp,0,sizeof dp);

        dp[0] = 1;

        int csum = 0 ; 

        for(int i = 1;i <= n; i ++)

        {

           scanf("%d %d",&ta,&tb);

           

          if(ta == 2 )

              sum += tb;

          else{

             csum += tb ;

             for(int i = csum;i >= 0 ;i -- )

             {

               if(dp[i] != 0 )

               {

                  dp[i+tb] = 1; 

               }

             }

          }

        }

        for(int i = csum /2 ;i >= 0 ;i--)

        {

          if(dp[i] != 0 )

          {

             sum += max(i,csum-i);

             break;

          }

        }

        printf("%d\n",sum);

             

    }

return 0;

}

View Code