Add solution #472

Author: JoshCrozier

README.md

@@ -277,6 +277,7 @@
 459|[Repeated Substring Pattern](./0459-repeated-substring-pattern.js)|Easy|
 461|[Hamming Distance](./0461-hamming-distance.js)|Easy|
 463|[Island Perimeter](./0463-island-perimeter.js)|Medium|
+472|[Concatenated Words](./0472-concatenated-words.js)|Hard|
 476|[Number Complement](./0476-number-complement.js)|Easy|
 482|[License Key Formatting](./0482-license-key-formatting.js)|Easy|
 485|[Max Consecutive Ones](./0485-max-consecutive-ones.js)|Easy|

solutions/0472-concatenated-words.js

@@ -0,0 +1,35 @@
+/**
+ * 472. Concatenated Words
+ * https://leetcode.com/problems/concatenated-words/
+ * Difficulty: Hard
+ *
+ * Given an array of strings words (without duplicates), return all the concatenated words
+ * in the given list of words.
+ *
+ * A concatenated word is defined as a string that is comprised entirely of at least two
+ * shorter words (not necessarily distinct) in the given array.
+ */
+
+/**
+ * @param {string[]} words
+ * @return {string[]}
+ */
+var findAllConcatenatedWordsInADict = function(words) {
+  const set = new Set(words);
+  const map = new Map();
+
+  function isValid(word) {
+    if (map.has(word)) return map.get(word);
+    for (let i = 1; i < word.length; i++) {
+      const suffix = word.slice(i);
+      if (set.has(word.slice(0, i)) && (set.has(suffix) || isValid(suffix))) {
+        map.set(word, true);
+        return true;
+      }
+    }
+    map.set(word, false);
+    return false;
+  }
+
+  return words.filter(word => word.length > 0 && isValid(word));
+};