LeetCode Entry

443. String Compression

02.03.2023 medium 2023 kotlin

Let's just do a naive toString for simplicity.

443. String Compression medium

blog post

fun compress(chars: CharArray): Int {
    var end = 0
    var curr = 0
    while (curr < chars.size) {
        val c = chars[curr++]
        var currCount = 1
        while (curr < chars.size && c == chars[curr]) {
            curr++
            currCount++
        }
        chars[end++] = c
        if (currCount > 1) currCount.toString().forEach { chars[end++] = it }
    }
    return end
}

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Intuition

You don’t need to split a number into groups of 9’s. The right way to convert number 123 into a string is to divide it by 10 each time, then reverse a part of the array.

Approach

• Let’s just do a naive toString for simplicity.
• to avoid mistakes with indexes, use explicit variable for count the duplicate chars

  Complexity

• Time complexity: \(O(n)\)
• Space complexity: \(O(lg_10(n))\), for storing toString. For this task it is a 4