schindlerlee原创，禁止转载和用于商业用途
此题意思很明显
把一个数从进制a转化到进制b
用C/C++写实在是太麻烦了，用java搞了一下，还是不熟啊，写了好久
1 //java catalan 数
2 import java.math.*;
3 import java.util.*;
4 import java.io.*;
5
6 public class Main {
7
8 public static void main(String[] args) {
9 Scanner cin = new Scanner(
10 new BufferedReader(
11 new InputStreamReader(System.in)));
12 //That is (in decimal) A = 10, B = 11, 
, Z = 35, a = 36, b = 37, , z = 61
13 int c = cin.nextInt();
14 while (c-- > 0) {
15 int a = cin.nextInt();
16 int b = cin.nextInt();
17 BigInteger r = BigInteger.valueOf(0);
18 BigInteger idx = BigInteger.valueOf(1);
19 String s = cin.next();
20 System.out.println(a + " " + s);
21 for (int i = s.length() - 1; i >= 0; i--, idx = idx.multiply(BigInteger.valueOf(a))) {
22 char t = s.charAt(i);
23 //8 62 2 abcdefghiz System.out.println("char t = " + t);
24 int add;
25 if (t >= '0' && t <= '9') {
26 add = t - '0';
27 } else if (t >= 'A' && t <= 'Z') {
28 add = t - 'A' + 10;
29 } else {
30 add = t - 'a' + 36;
31 }
32 r = r.add(idx.multiply(BigInteger.valueOf(add)));
33 }
34
35 // System.out.println(r.toString());
36 String res = "";
37 idx = BigInteger.valueOf(b);
38 if (s.equals("0")) {
39 System.out.println(b + " 0");
40 } else {
41 while (r.compareTo(BigInteger.ZERO) > 0) {
42 BigInteger ad[];
43 ad = r.divideAndRemainder(idx);
44 r = ad[0];
45 int t = ad[1].intValue();
46 char ch;
47 if (t >= 0 && t <= 9) {
48 ch = (char) (t + '0');
49 } else if (t >= 10 && t <= 35) {
50 ch = (char) (t - 10 + 'A');
51 } else {
52 ch = (char) (t - 36 + 'a');
53 }
54 res = ch + res;
55 // System.out.println("ad[0]= "+ad[0]);
56 // System.out.println("ad[1]= "+ad[1]);
57 }
58 System.out.println(b + " " + res);
59 }
60 System.out.print('\n');
61 //System.out.println("res = "+res);
62 }
63 }
64 }
65
66