LeetCode in Kotlin

1170. Compare Strings by Frequency of the Smallest Character

Medium

Let the function f(s) be the frequency of the lexicographically smallest character in a non-empty string s. For example, if s = "dcce" then f(s) = 2 because the lexicographically smallest character is 'c', which has a frequency of 2.

You are given an array of strings words and another array of query strings queries. For each query queries[i], count the number of words in words such that f(queries[i]) < f(W) for each W in words.

Return an integer array answer, where each answer[i] is the answer to the ith query.

Example 1:

Input: queries = [“cbd”], words = [“zaaaz”]

Output: [1]

Explanation: On the first query we have f(“cbd”) = 1, f(“zaaaz”) = 3 so f(“cbd”) < f(“zaaaz”).

Example 2:

Input: queries = [“bbb”,”cc”], words = [“a”,”aa”,”aaa”,”aaaa”]

Output: [1,2]

Explanation: On the first query only f(“bbb”) < f(“aaaa”). On the second query both f(“aaa”) and f(“aaaa”) are both > f(“cc”).

Constraints:

• 1 <= queries.length <= 2000
• 1 <= words.length <= 2000
• 1 <= queries[i].length, words[i].length <= 10
• queries[i][j], words[i][j] consist of lowercase English letters.

Solution

class Solution {
    fun numSmallerByFrequency(queries: Array<String>, words: Array<String>): IntArray {
        val queriesMinFrequecies = IntArray(queries.size)
        for (i in queries.indices) {
            queriesMinFrequecies[i] = computeLowestFrequency(queries[i])
        }
        val wordsMinFrequecies = IntArray(words.size)
        for (i in words.indices) {
            wordsMinFrequecies[i] = computeLowestFrequency(words[i])
        }
        wordsMinFrequecies.sort()
        val result = IntArray(queries.size)
        for (i in result.indices) {
            result[i] = search(wordsMinFrequecies, queriesMinFrequecies[i])
        }
        return result
    }

    private fun search(nums: IntArray, target: Int): Int {
        var count = 0
        for (i in nums.indices.reversed()) {
            if (nums[i] > target) {
                count++
            } else {
                break
            }
        }
        return count
    }

    private fun computeLowestFrequency(string: String): Int {
        val str = string.toCharArray()
        str.sort()
        val sortedString = String(str)
        var frequency = 1
        for (i in 1 until sortedString.length) {
            if (sortedString[i] == sortedString[0]) {
                frequency++
            } else {
                break
            }
        }
        return frequency
    }
}

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