LeetCode in Kotlin

3675. Minimum Operations to Transform String

Medium

You are given a string s consisting only of lowercase English letters.

You can perform the following operation any number of times (including zero):

• Choose any character c in the string and replace every occurrence of c with the next lowercase letter in the English alphabet.

Return the minimum number of operations required to transform s into a string consisting of only 'a' characters.

Note: Consider the alphabet as circular, thus 'a' comes after 'z'.

Example 1:

Input: s = “yz”

Output: 2

Explanation:

• Change 'y' to 'z' to get "zz".
• Change 'z' to 'a' to get "aa".
• Thus, the answer is 2.

Example 2:

Input: s = “a”

Output: 0

Explanation:

• The string "a" only consists of 'a' characters. Thus, the answer is 0.

Constraints:

• 1 <= s.length <= 5 * 105
• s consists only of lowercase English letters.

Solution

class Solution {
    fun minOperations(s: String): Int {
        val n = s.length
        var ans = 0
        for (i in 0..<n) {
            val c = s[i]
            if (c != 'a') {
                val ops = 'z'.code - c.code + 1
                if (ops > ans) {
                    ans = ops
                }
                if (ops == 25) {
                    break
                }
            }
        }
        return ans
    }
}

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