LeetCode in Kotlin

1002. Find Common Characters

Easy

Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order.

Example 1:

Input: words = [“bella”,”label”,”roller”]

Output: [“e”,”l”,”l”]

Example 2:

Input: words = [“cool”,”lock”,”cook”]

Output: [“c”,”o”]

Constraints:

• 1 <= words.length <= 100
• 1 <= words[i].length <= 100
• words[i] consists of lowercase English letters.

Solution

class Solution {
    fun commonChars(words: Array<String>?): List<String> {
        if (words == null) {
            throw RuntimeException("words null")
        }
        if (words.isEmpty()) {
            return ArrayList()
        }
        var tmp = words[0]
        for (i in 1 until words.size) {
            tmp = getCommon(tmp, words[i])
        }
        val result: MutableList<String> = ArrayList()
        for (element in tmp) {
            result.add(element.toString())
        }
        return result
    }

    private fun getCommon(s1: String, s2: String): String {
        if (s1.isEmpty() || s2.isEmpty()) {
            return ""
        }
        val c1c = countChars(s1)
        val c2c = countChars(s2)
        val sb = StringBuilder()
        for (i in c1c.indices) {
            var m = c1c[i].coerceAtMost(c2c[i])
            while (m > 0) {
                sb.append(('a'.code + i).toChar())
                m--
            }
        }
        return sb.toString()
    }

    private fun countChars(str: String): IntArray {
        val result = IntArray(26)
        for (element in str) {
            result[element.code - 'a'.code]++
        }
        return result
    }
}

This site is open source. Improve this page.