Base62 大數

題目

https://nanti.jisuanke.com/t/42389

題意

進制轉換

思路

java大數

代碼

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

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner cin = new Scanner(System.in);
		String s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
		BigInteger[] num = new BigInteger[200];
		for(int i = 0;i <= 61;i++)
		{
			int x = s.charAt(i);
			String tt = ""+i;
			num[x] = new BigInteger(tt.toString()); 
		}
		BigInteger q,w;
		String qi;
		q = cin.nextBigInteger();
		w = cin.nextBigInteger();
		qi = cin.next();
		BigInteger qw = new BigInteger("0");
		BigInteger ling = new BigInteger("0");
		int len = qi.length();
		for(int i = 0;i <= len-1;i++)
		{
			char x = qi.charAt(i);
			qw = qw.multiply(q);
			int zz = x;
			qw = qw.add(num[zz]);
		}
		
		char[] ans = new char[2000];
		int p = 0;
//		System.out.println(qw);
		while(true)
		{
//			System.out.println(qw);
			BigInteger yu;
			yu = qw.mod(w);
			qw = qw.divide(w);
			int yuu;
			String str=yu.toString();
			yuu=Integer.parseInt(str);
//			System.out.println(qw + " "+yu);
			ans[p] = s.charAt(yuu);
			p++;
			if(qw.compareTo(ling) == 0) break;
		}
		
		for(int i = p-1;i >= 0;i--)
		{
			System.out.print(ans[i]);
		}
		System.out.print("\n");
	}





}