1844-ReplaceAllDigitsWithCharacters.go

package main

// 1844. Replace All Digits with Characters
// You are given a 0-indexed string s that has lowercase English letters in its even indices and digits in its odd indices.

// You must perform an operation 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 the result of the shift(s[i-1], s[i]) operation.

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

// Note that shift(c, x) is not a preloaded function, but an operation to be implemented as part of the solution.

// 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.

import "fmt"

func replaceDigits(s string) string {
    res := []byte(s)
    isNumber := func (c byte) bool { return '0' <= c && c <= '9' }
    for i, v := range res {
        if isNumber(v) {
            res[i] = (res[i - 1] + (v - '0'))
        }
    }
    return string(res)
}

func main() {
// 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'
fmt.Println(replaceDigits("a1c1e1")) // abcdef
// 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'
fmt.Println(replaceDigits("a1b2c3d4e")) // abbdcfdhe
}