LeetCode in Kotlin

1737. Change Minimum Characters to Satisfy One of Three Conditions

Medium

You are given two strings a and b that consist of lowercase letters. In one operation, you can change any character in a or b to any lowercase letter.

Your goal is to satisfy one of the following three conditions:

• Every letter in a is strictly less than every letter in b in the alphabet.
• Every letter in b is strictly less than every letter in a in the alphabet.
• Both a and b consist of only one distinct letter.

Return the minimum number of operations needed to achieve your goal.

Example 1:

Input: a = “aba”, b = “caa”

Output: 2

Explanation: Consider the best way to make each condition true:

1) Change b to “ccc” in 2 operations, then every letter in a is less than every letter in b.

2) Change a to “bbb” and b to “aaa” in 3 operations, then every letter in b is less than every letter in a.

3) Change a to “aaa” and b to “aaa” in 2 operations, then a and b consist of one distinct letter. The best way was done in 2 operations (either condition 1 or condition 3).

Example 2:

Input: a = “dabadd”, b = “cda”

Output: 3

Explanation: The best way is to make condition 1 true by changing b to “eee”.

Constraints:

• 1 <= a.length, b.length <= 105
• a and b consist only of lowercase letters.

Solution

class Solution {
    fun minCharacters(a: String, b: String): Int {
        val array1 = IntArray(26)
        val array2 = IntArray(26)
        val l1: Int = a.length
        val l2: Int = b.length
        for (i: Char in a.toCharArray()) {
            array1[i.code - 'a'.code]++
        }
        for (i: Char in b.toCharArray()) {
            array2[i.code - 'a'.code]++
        }
        var min: Int = Int.MAX_VALUE
        var t1 = 0
        var t2 = 0
        var max: Int = -1
        for (i in 0..24) {
            t1 += array1[i]
            t2 += array2[i]
            min = Math.min(min, Math.min(t1 + l2 - t2, t2 + l1 - t1))
            max = Math.max(max, array1[i] + array2[i])
        }
        max = Math.max(max, array1[25] + array2[25])
        return Math.min(min, l1 + l2 - max)
    }
}

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