HRBUST 1212 乘积最大

Posted 2020-09-03 Fighting Heart

$dp$，大数运算。

$dp[i][j]$表示到$i$位置切成了$j$段的最大收益。数字爆$longlong$，$Java$上大数。

import java.math.BigInteger;
import java.util.Scanner;


public class Main {
    
    static BigInteger MAX(BigInteger a,BigInteger b)
    {
        if(a.compareTo(b)>=0) return a;
        return b;
    }
    
    public static void main(String args[]){
        Scanner cin = new Scanner(System.in);
        int n,k;
        String x; 
        BigInteger  dp[][] = new BigInteger [50][10];
        
        while(cin.hasNext())
        {
            n = cin.nextInt();
            k = cin.nextInt(); k++;
            x = cin.next();
            
            for(int i=0;i<x.length();i++)
            {
                for(int j=1;j<=k;j++) dp[i][j] = BigInteger.ZERO;
            }
            
            String y = "";
            for(int i=0;i<x.length();i++)
            {
                y=y+x.charAt(i);
                dp[i][1] = new BigInteger(y);
            }
            
            for(int j=2;j<=k;j++)
            {
                for(int i=j-1;i<x.length();i++)
                {
                    for(int p=j-2;p<i;p++)
                    {
                        y =  "";
                        for(int g=p+1;g<=i;g++) y=y+x.charAt(g);
                        dp[i][j]=MAX(dp[i][j],dp[p][j-1].multiply(new BigInteger(y)));
                    }
                }
            }
            
            System.out.println(dp[x.length()-1][k]);
            
        }
    }
}