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".
public class Solution {
public int TitleToNumber(string s) {
int res = 0;
for(int i=s.Length-1, j=0;i>=0;i--,j++){
res += (int)Math.Pow(26,j)*(s[i]-64);
}
return res;
}
}Time Complexity: O(n)
Space Complexity: O(1)
