replace-all-digits-with-characters_1844.py

# You are given a 0-indexed string s that has lowercase English letters in its even indices and digits in its odd indices.

# There is a function shift(c, x), where c is a character and x is a digit, that returns the xth character after c.

# For example, shift('a', 5) = 'f' and shift('x', 0) = 'x'.
# For every odd index i, you want to replace the digit s[i] with shift(s[i-1], s[i]).

# Return s after replacing all digits. It is guaranteed that shift(s[i-1], s[i]) will never exceed 'z'.

# Example 1:

# Input: s = "a1c1e1"
# Output: "abcdef"
# Explanation: The digits are replaced as follows:
# - s[1] -> shift('a',1) = 'b'
# - s[3] -> shift('c',1) = 'd'
# - s[5] -> shift('e',1) = 'f'
# Example 2:

# Input: s = "a1b2c3d4e"
# Output: "abbdcfdhe"
# Explanation: The digits are replaced as follows:
# - s[1] -> shift('a',1) = 'b'
# - s[3] -> shift('b',2) = 'd'
# - s[5] -> shift('c',3) = 'f'
# - s[7] -> shift('d',4) = 'h'
# Constraints:

# 1 <= s.length <= 100
# s consists only of lowercase English letters and digits.
# shift(s[i-1], s[i]) <= 'z' for all odd indices i.

# ---------------------------------------Runtime 33 ms Beats 74.27% Memory 16.54 MB Beats 44.27%---------------------------------------


class Solution:
    def replaceDigits(self, s: str) -> str:
        res: str = []
        prev = ""
        for char in s:
            if char.isdigit():
                char = chr(ord(prev) + int(char))
            prev = char
            res.append(char)
        return "".join(res)