华为2017年8月30日校招编程真题2-自定义的26进制和十进制之间互相转换

题目

思路

AC（通过70+%，没查出错误）

package test.test2;

import org.junit.Test;

/**
* description:
*
* @author liyazhou
* @since 2017-08-30 19:57
*/
public class Main {

@Test
public void test(){
String[] strs = {"a",
"aa",
"aaa",
"ab",
"az",
"z",
"i",
"huawei",
"26",
"27",
"27",
"27",
"104680767",
};
for (String str: strs){
String result = convertTo26(str);
System.out.println(str + " :: " + result);
}
}

//    public static void main(String[] args){
//        Scanner sc = new Scanner(System.in);
//        String s = sc.next();
//        String result = new Main().convertTo26(s);
//        System.out.println(result);
//    }

public String convertTo26(String str){
char[] chars = str.toCharArray();
String result = "";
if (chars[0] >= '0' && chars[0] <= '9'){
result = numToStr(chars);
}else{
result = strToNum(chars) + "";
}

return result;
}

private String numToStr(char[] chars){
StringBuilder result = new StringBuilder();
int num = Integer.valueOf(new String(chars));
while (num != 0){
int re = num % 26;
if (re > 0){
char r = (char)(re + ('a' - 1));
result.append(r);
}
num  /= 26;
}
return result.reverse().toString();
}

private int strToNum(char[] chars){
int num = 0;
int counter = 0;
int base = 1;
for (int i = chars.length-1; i >= 0; i --){
base = 1;
for (int j = 0; j < counter; j ++){
base *= 26;
}
num += (chars[i] - 'a' + 1) * base;
counter ++;
}
return num;
}
}