原題連接：

• P1143 進(jìn)制轉(zhuǎn)換

題目

// 方法1:不用Integer
public class Main{
    static int First ;
    static String num ;
    static int Last ;
    static long tenNum ;
    static String ans ;
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        First = sc.nextInt();
        num = sc.next();
        Last = sc.nextInt();
        tenNum = 0;
        ans = "";
        
        String[] str = num.split("");
        
        for (int i = 0; i < str.length; i++) {
            switch(str[i]) {
                case "A" :
                    str[i] = "10";
                    break;
                case "B" :
                    str[i] = "11";
                    break;
                case "C" :
                    str[i] = "12";
                    break;
                case "D" :
                    str[i] = "13";
                    break;
                case "E" :
                    str[i] = "14";
                    break;
                case "F" :
                    str[i] = "15";
                    break;
            }
            
            
        }
        to_TEN(First,str);
        
        to_AIM(Last,tenNum);
        
        System.out.println(ans);        
    }

    private static void to_AIM(int l, long ten) {
        int cur = 0;
        while(ten > 0) {
            cur = (int) (ten%l);
            ten = ten / l;
            if (cur > 9) {
                switch(cur) {
                case 10 :
                    ans = "A"+ans;
                    break;
                case 11 :
                    ans = "B"+ans;
                    break;
                case 12 :
                    ans = "C"+ans;
                    break;
                case 13 :
                    ans = "D"+ans;
                    break;
                case 14 :
                    ans = "E"+ans;
                    break;
                case 15 :
                    ans = "F"+ans;
                    break;
                }
            }else {
                ans = cur+ans;
            }           
        }       
    }

    private static void to_TEN(int f ,String[] s) {     
        for (int i = 0; i < s.length; i++) {
            int curNum = 0 ;
            for (int j = 0; j < s[i].length(); j++) {
                curNum *= 10;
                curNum += (s[i].charAt(j) - '0');
            }           
            tenNum = (tenNum * f) + curNum;
        }       
    }

}

// 方法2
public class P1143_JinZhiZhuanHuan_M2 {
    public static void main(String[] args) {
        long dp[][][] = new long[22][22][22];
        Scanner in = new Scanner(System.in);
        String n = in.nextLine();
        String s = in.nextLine();
        int n2 = in.nextInt();
        int k = Integer.valueOf(n);
        k = Integer.valueOf(s, k);
        System.out.println(Integer.toString(k, n2).toUpperCase());
    }

}