60 lines
1.6 KiB
Kotlin
60 lines
1.6 KiB
Kotlin
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class Solution {
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private fun precomputeFrom(
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words: List<String>,
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s: String,
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dp: Map<Int, List<String>>,
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start: Int,
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): List<String> {
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val valid = mutableListOf<String>()
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(start..<s.length)
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.map { end -> end to s.substring(start..end) }
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.filter { (_, word) -> words.contains(word) }
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.forEach { (end, word) ->
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when {
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end == s.length - 1 -> valid.add(word)
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else -> {
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dp[end + 1]?.forEach { suffix ->
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valid.add("$word $suffix")
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}
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}
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}
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}
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return valid
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}
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fun wordBreak(
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s: String,
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wordDict: List<String>,
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): List<String> {
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val dp = mutableMapOf<Int, List<String>>()
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s.indices.reversed().forEach { start ->
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dp[start] = precomputeFrom(wordDict, s, dp, start)
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}
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return dp.getOrDefault(0, emptyList())
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}
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}
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fun main() {
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val s = Solution()
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check(
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s.wordBreak("catsanddog", listOf("cat", "cats", "and", "sand", "dog")).sorted() ==
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listOf(
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"cats and dog", "cat sand dog",
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).sorted(),
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)
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check(
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s.wordBreak("pineapplepenapple", listOf("apple", "pen", "applepen", "pine", "pineapple")).sorted() ==
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listOf(
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"pine apple pen apple", "pineapple pen apple", "pine applepen apple",
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).sorted(),
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)
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check(
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s.wordBreak("catsandog", listOf("cats", "dog", "sand", "and", "cat")) == emptyList<String>(),
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)
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}
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