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"
Example 4:
Input: columnNumber = 2147483647 Output: "FXSHRXW"
Constraints:
1 <= columnNumber <= 231 - 1
Solution:
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/**
* Time Complexity: O(n)
* Space Complexity: constant .
**/
class Solution {
public String convertToTitle(int col) {
StringBuilder sb = new StringBuilder();
while(col > 0) {
int x = col % 26;
int rem = x == 0 ? 26 : x;
sb.append((char)(64 + rem));
col = (col - rem)/ 26 ;
}
return sb.reverse().toString();
}
}
