• Question
• Solution

Question

Related to question Excel Sheet Column Title

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

Solution

Result: Accepted Time: 8 ms

Here should be some explanations.

int titleToNumber(char* s) {
    int ret = 0;
    while(*s)
        ret = ret * 26 + *(s++) - 'A' + 1;
    return ret;
}

Complexity Analytics

• Time Complexity: $O(n)$
• Space Complexity: $O(1)$