Excel_Sheet_Column_Number.py

# 171. Excel Sheet Column Number
# Given a string columnTitle that represents the column title as appears 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: columnTitle = "A"
# Output: 1
# Example 2:

# Input: columnTitle = "AB"
# Output: 28
# Example 3:

# Input: columnTitle = "ZY"
# Output: 701
 

# Constraints:

# 1 <= columnTitle.length <= 7
# columnTitle consists only of uppercase English letters.
# columnTitle is in the range ["A", "FXSHRXW"].

# solution
class Solution:
    def titleToNumber(self, columnTitle: str) -> int:


        result = 0;
        for B in range(len(columnTitle)):
             result *= 26;
             result += ord(columnTitle[B]) - ord('A') + 1;
 
        return result;