LeetCode [171] Excel Sheet Column Number

 171. Excel Sheet Column Number

Easy

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

 

Constraints:

• 1 <= s.length <= 7
• s consists only of uppercase English letters.
• s is between "A" and "FXSHRXW".

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class Solution { public: int titleToNumber(string s) { int res = 0; int n = s.size(); for(int i=0; i<n; ++i){ res = res*26+(s[i]-'A'+1); } return res; } };

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class Solution { public int titleToNumber(String s) { int x = 0; for(char c : s.toCharArray()){ int k = c - 'A'; x = x*26+k+1; } return x; } }