zoukankan      html  css  js  c++  java
  • hdu 4628 Pieces(状态压缩+记忆化搜索)

    Pieces

    Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)
    Total Submission(s): 1811    Accepted Submission(s): 932


    Problem Description
    You heart broke into pieces.My string broke into pieces.But you will recover one day,and my string will never go back.
    Given a string s.We can erase a subsequence of it if this subsequence is palindrome in one step. We should take as few steps as possible to erase the whole sequence.How many steps do we need?
    For example, we can erase abcba from axbyczbea and get xyze in one step.
     

    Input
    The first line contains integer T,denote the number of the test cases. Then T lines follows,each line contains the string s (1<= length of s <= 16).
    T<=10.
     

    Output
    For each test cases,print the answer in a line.
     

    Sample Input
    2 aa abb
     

    Sample Output
    1 2
     

    Author
    WJMZBMR
     

    Source
    题意:给一个字符串,长度<=16,每次去掉一个回文串。能够中不连续的。问最少用多少次把所给的串都去掉。
    解题:先用状态压缩把回文串的状态标记。再用记忆化搜索或dp。
    #include<stdio.h>
    #include<string.h>
    const int inf=20;
    int dp[1<<17],len,flag[1<<17];
    char str[20];
    bool judge(int sta){
        char s[20];
        int k=0 , l , r;
        for(int i=0; (1<<i)<=sta; i++)
            if((1<<i)&sta)
            s[k++]=str[i];
        if(k==0)return 0;
        if(k==1)return 1;
        if(k&1){
            l=k/2-1; r=l+2;
        }
        else{
            l=k/2-1; r=l+1;
        }
        while(r<k&&s[l]==s[r])l--,r++;
        if(r<k)return 0;
        else return 1;
    }
    void dfs(int sta){
        if(dp[sta]!=inf)
            return ;
        for(int s=sta-1;s>0; s=(s-1)&sta){
            if(!flag[s^sta])continue;
            dfs(s);
            if(dp[sta]>dp[s]+1)
                dp[sta]=dp[s]+1;
        }
        if(judge(sta))
            if(dp[sta]>1)
                dp[sta]=1;
    }
    int main()
    {
        int T;
        scanf("%d",&T);
        while(T--){
            scanf("%s",str);
            len=strlen(str);
            for(int i=(1<<len)-1; i>0; i--){
                dp[i]=inf;
                flag[i]=judge(i);
            }
            dp[0]=0;flag[0]=0;
    
            dfs((1<<len)-1);
            printf("%d
    ",dp[(1<<len)-1]);
        }
        return 0;
    }
    


     
  • 相关阅读:
    paip.erlang 文本文件读写操作attilax总结
    paip.python错误解决20
    paip.python错误解决8
    paip. sip module implements API v10.0 to v10.1 but the PyQt4.QtCore module requires API v9.2
    解读NoSQL数据库的四大家族
    paip.python错误解决9
    paip.python 执行shell 带空格命令行attilax总结
    paip.python错误解决15
    paip.python错误解决24
    paip.python优缺点attilax总结
  • 原文地址:https://www.cnblogs.com/llguanli/p/7010523.html
Copyright © 2011-2022 走看看