181.Excel Sheet Column Title
题目:
Given a positive integer, return its corresponding column title as appear in an Excel sheet.
给定正整数,返回Excel工作表中显示的相应列标题。
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"
解答:
方法一:
1 class Solution { 2 public String convertToTitle(int n) { 3 String res=""; 4 while(n>0){ 5 res=(char)((--n)%26+'A')+res; //注意不能写成res+=,不然会逆序,还要进行反转操作 6 n/=26; 7 } 8 return res; 9 } 10 }
方法二:递归
1 class Solution { 2 public String convertToTitle(int n) { 3 return n==0 ? "":convertToTitle(--n/26)+(char)(n%26+'A'); 4 } 5 }
详解: