POJ 1220 （两种任意进制之间的转换（大数），java的BigInteger）

迷南。 2022-09-17 12:23 160阅读 0赞

http://poj.org/problem?id=1220

N进制 向 M进制 转换，

1. 先将N进制 转换成10进制；

2.将结果逐次对M取余；

一开始用BigDecimal，没办法取余；参考大神的，用BigInteger

package com.zyh.hdu;
    
    
    import java.math.BigInteger;
    import java.util.Scanner;
    
    public class Poj1220 {
    	public static void main(String[] args) {
    		Scanner cin = new Scanner(System.in);
    		
    		int t = cin.nextInt();
    		while(t-- != 0){
    		
    			int a = cin.nextInt();
    			int b = cin.nextInt();
    			String aa = cin.next();
    			System.out.println(a+" "+aa);
    			System.out.print(b+" ");
    			
    			 BigInteger sum = BigInteger.ZERO;
    			for(int i=0; i<aa.length();i++){
    				sum = sum.multiply(BigInteger.valueOf(a)).add(BigInteger.valueOf(getnum(aa.charAt(i))));
    			}
    			//System.out.println(sum);
    			
    			String bb = "";
    			
    			while(!sum.equals(BigInteger.ZERO)){
    				bb = retchar(sum.mod(BigInteger.valueOf(b)).intValue()) + bb;
    				sum = sum.divide(BigInteger.valueOf(b));
    			}
    			if(bb.equals("")) bb="0";
    			System.out.println(bb);
    			System.out.println();
    		}
    	}
    	static int getnum(char m){
    		if(m>='0' && m<='9') return m - '0';
    		else if(m>='A' && m<='Z') return m-'A'+10;
    		else return m-'a'+36;
    	}
    	static char retchar(int i){
    		if(i<=9) return (char) (i + '0');
    		else if(i>=10 && i<=35) return (char)(i -10+'A');
    		else return (char)(i-36+'a');
    	}
    }
    
    
    /*
     * 
     * 
     * 
    Sample Input
    
    8
    62 2 abcdefghiz
    10 16 1234567890123456789012345678901234567890
    16 35 3A0C92075C0DBF3B8ACBC5F96CE3F0AD2
    35 23 333YMHOUE8JPLT7OX6K9FYCQ8A
    23 49 946B9AA02MI37E3D3MMJ4G7BL2F05
    49 61 1VbDkSIMJL3JjRgAdlUfcaWj
    61 5 dl9MDSWqwHjDnToKcsWE1S
    5 10 42104444441001414401221302402201233340311104212022133030
    
    Sample Output
    
    62 abcdefghiz
    2 11011100000100010111110010010110011111001001100011010010001
    
    10 1234567890123456789012345678901234567890
    16 3A0C92075C0DBF3B8ACBC5F96CE3F0AD2
    
    16 3A0C92075C0DBF3B8ACBC5F96CE3F0AD2
    35 333YMHOUE8JPLT7OX6K9FYCQ8A
    
    35 333YMHOUE8JPLT7OX6K9FYCQ8A
    23 946B9AA02MI37E3D3MMJ4G7BL2F05
    
    23 946B9AA02MI37E3D3MMJ4G7BL2F05
    49 1VbDkSIMJL3JjRgAdlUfcaWj
    
    49 1VbDkSIMJL3JjRgAdlUfcaWj
    61 dl9MDSWqwHjDnToKcsWE1S
    
    61 dl9MDSWqwHjDnToKcsWE1S
    5 42104444441001414401221302402201233340311104212022133030
    
    5 42104444441001414401221302402201233340311104212022133030
    10 1234567890123456789012345678901234567890
     
     */