leetcode-168-easy

Excel Sheet Column Title

Given an integer columnNumber, return its corresponding column title as it appears in an Excel sheet.

For example:

A -> 1
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28 
...
Example 1:

Input: columnNumber = 1
Output: "A"
Example 2:

Input: columnNumber = 28
Output: "AB"
Example 3:

Input: columnNumber = 701
Output: "ZY"
Constraints:

1 <= columnNumber <= 231 - 1

思路一：刚开始想到是用 26 进制来实现，但是发现有个 0 干扰...

public String convertToTitle(int columnNumber) {
    StringBuffer sb = new StringBuffer();
    while (columnNumber != 0) {
        columnNumber--;
        sb.append((char)(columnNumber % 26 + 'A'));
        columnNumber /= 26;
    }
    return sb.reverse().toString();
}