题解 | 进制转换

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        Map<Character,Integer> map = new HashMap<>();
        map.put('A',10);map.put('B',11);map.put('C',12);
        map.put('D',13);map.put('E',14);map.put('F',15);
        int result =  0;
        int multiNum = 1;
        for(int i = s.length()-1; i>=2 ;i --){
            int curDigit = 0;
            if(s.charAt(i) >= 'A' && s.charAt(i) <= 'F'){
            curDigit = map.get(s.charAt(i));
            }else{
            curDigit = s.charAt(i) - '0';
            }
            result += curDigit * multiNum;
            multiNum *= 16;
        }
        System.out.println(result);
    }
}