2016年腾讯笔试题——构造回文

import java.util.Scanner;
import java.lang.Math;

public class Main {
    static int[][] dp = new int[1010][1010];

    public static int GetMax(String str){
        StringBuffer buf = new StringBuffer();
        String reverse = buf.append(str).reverse().toString();
        int len = str.length();
        for ( int i = 1 ; i <= len ; i++){
            for ( int j = 1 ; j <= len ; j++){
                if ( str.charAt(i-1) == reverse.charAt(j-1)){
                    dp[i][j] = dp[i-1][j-1]+1;
                }else{
                    dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]);
                }
            }
        }
        return dp[len][len];
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String str;
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            str = in.next();
            System.out.println(str.length() - GetMax(str));
        }
        in.close();
    }

}