Given a column title as appear in an Excel sheet, return its corresponding column number.
For example:
A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28 ...
Example 1:
Input: "A" Output: 1
Example 2:
Input: "AB" Output: 28
Example 3:
Input: "ZY" Output: 701
分析¶
相当于把26进制数转换为10进制数字。从最低位到最高位依次转换,某一位的系数用addOn
表示。
public int titleToNumber(String s) { int res = 0; int n = s.length(); int addOn = 1; for (int i = 0; i < n; i++) { res += addOn*(s.charAt(n - i - 1) - 'A' + 1); addOn = addOn*26; } return res; }
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