168.Excel-Sheet-Column-Title

168. Excel Sheet Column Title

题目地址

题目描述

Given a positive integer, return its corresponding column title as appear in an Excel sheet.
​
For example:
1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB
...
​
Example 1:
Input: 1
Output: "A"
​
Example 2:
Input: 28
Output: "AB"
​
Example 3:
Input: 701
Output: "ZY"

代码

Approach 1:

class Solution {
public String convertToTitle(int n) {
StringBuilder result = new StringBuilder();
while (n > 0) {
n--;
result.insert(0, (char)('A' + n % 26));
n /= 26;
}
​
return result.toString();
}
}

Approach #2

public class Solution {
public String convertToTitle(int n) {
String res = "";
while(n != 0) {
char ch = (char)((n - 1) % 26 + 65);
n = (n - 1) / 26;
res = ch + res;
}
return res;
}
}