LeetCode in Kotlin

557. Reverse Words in a String III

Easy

Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: s = “Let’s take LeetCode contest”

Output: “s’teL ekat edoCteeL tsetnoc”

Example 2:

Input: s = “God Ding”

Output: “doG gniD”

Constraints:

• 1 <= s.length <= 5 * 104
• s contains printable ASCII characters.
• s does not contain any leading or trailing spaces.
• There is at least one word in s.
• All the words in s are separated by a single space.

Solution

@Suppress("NAME_SHADOWING")
class Solution {
    fun reverseWords(s: String): String {
        var l: Int
        var r = 0
        val len = s.length
        val ch = s.toCharArray()
        for (i in 0..len) {
            if (i == len || ch[i] == ' ') {
                l = r
                r = i
                reverse(ch, l, r - 1)
                r++
            }
        }
        return String(ch)
    }

    private fun reverse(s: CharArray, l: Int, r: Int) {
        var l = l
        var r = r
        var c: Char
        while (r > l) {
            c = s[l]
            s[l++] = s[r]
            s[r--] = c
        }
    }
}

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