171. Excel Sheet Column Number (E)

Excel Sheet Column Number (E)

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

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题意

将给定字母字符串转换为对应的整数。

思路

26进制转换。

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代码实现

class Solution {
    public int titleToNumber(String s) {
        int ans = 0;
        for (int i = 0; i < s.length(); i++) {
            int x = s.charAt(i) - 'A' + 1;
            ans = ans * 26 + x;
        }
        return ans;
    }
}