rep_digts.go

package problem1844

/*
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'.
*/

const diff = '0'

func replaceDigits(s string) string {
	var res = make([]byte, len(s))
	for i := 0; i < len(s); i++ {
		if i%2 == 0 {
			res[i] = s[i]
		} else {
			res[i] = s[i-1] + (s[i] - diff)
		}
	}
	return string(res)
}