LeetCode in Kotlin

1178. Number of Valid Words for Each Puzzle

Hard

With respect to a given puzzle string, a word is valid if both the following conditions are satisfied:

• word contains the first letter of puzzle.
• For each letter in word, that letter is in puzzle.
  • For example, if the puzzle is "abcdefg", then valid words are "faced", "cabbage", and "baggage", while
  • invalid words are "beefed" (does not include 'a') and "based" (includes 's' which is not in the puzzle).

Return an array answer, where answer[i] is the number of words in the given word list words that is valid with respect to the puzzle puzzles[i].

Example 1:

Input: words = [“aaaa”,”asas”,”able”,”ability”,”actt”,”actor”,”access”], puzzles = [“aboveyz”,”abrodyz”,”abslute”,”absoryz”,”actresz”,”gaswxyz”]

Output: [1,1,3,2,4,0]

Explanation:

1 valid word for “aboveyz” : “aaaa”

1 valid word for “abrodyz” : “aaaa”

3 valid words for “abslute” : “aaaa”, “asas”, “able”

2 valid words for “absoryz” : “aaaa”, “asas”

4 valid words for “actresz” : “aaaa”, “asas”, “actt”, “access”

There are no valid words for “gaswxyz” cause none of the words in the list contains letter ‘g’.

Example 2:

Input: words = [“apple”,”pleas”,”please”], puzzles = [“aelwxyz”,”aelpxyz”,”aelpsxy”,”saelpxy”,”xaelpsy”]

Output: [0,1,3,2,0]

Constraints:

• 1 <= words.length <= 105
• 4 <= words[i].length <= 50
• 1 <= puzzles.length <= 104
• puzzles[i].length == 7
• words[i] and puzzles[i] consist of lowercase English letters.
• Each puzzles[i] does not contain repeated characters.

Solution

class Solution {
    fun findNumOfValidWords(words: Array<String>, puzzles: Array<String>): List<Int> {
        val ans: MutableList<Int> = ArrayList()
        val map = HashMap<Int, Int>()
        for (word in words) {
            val wordmask = createMask(word)
            if (map.containsKey(wordmask)) {
                val oldfreq = map.getValue(wordmask)
                val newfreq = oldfreq + 1
                map[wordmask] = newfreq
            } else {
                map[wordmask] = 1
            }
        }
        for (puzzle in puzzles) {
            val puzzlemask = createMask(puzzle)
            val firstChar = puzzle[0]
            val first = 1 shl firstChar.code - 'a'.code
            var sub = puzzlemask
            var count = 0
            while (sub != 0) {
                val firstCharPresent = sub and first == first
                val wordvalid = map.containsKey(sub)
                if (firstCharPresent && wordvalid) {
                    count += map.getValue(sub)
                }
                sub = sub - 1 and puzzlemask
            }
            ans.add(count)
        }
        return ans
    }

    private fun createMask(str: String): Int {
        var mask = 0
        for (i in 0 until str.length) {
            val bit = str[i].code - 'a'.code
            mask = mask or (1 shl bit)
        }
        return mask
    }
}

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