word break solution

Author: hyer0705

word-break/hyer0705.ts

@@ -0,0 +1,71 @@
+class TNode {
+  isEndOf: boolean;
+  children: Map<string, TNode>;
+
+  constructor() {
+    this.isEndOf = false;
+    this.children = new Map<string, TNode>();
+  }
+}
+
+class Trie {
+  root: TNode;
+
+  constructor() {
+    this.root = new TNode();
+  }
+
+  insert(word: string): void {
+    let currentNode = this.root;
+
+    for (const ch of word) {
+      if (!currentNode.children.has(ch)) {
+        currentNode.children.set(ch, new TNode());
+      }
+
+      currentNode = currentNode.children.get(ch)!;
+    }
+
+    currentNode.isEndOf = true;
+  }
+
+  search(word: string): boolean {
+    let currentNode = this.root;
+
+    for (const ch of word) {
+      if (!currentNode.children.has(ch)) {
+        return false;
+      }
+
+      currentNode = currentNode.children.get(ch)!;
+    }
+
+    return currentNode.isEndOf;
+  }
+}
+
+function wordBreak(s: string, wordDict: string[]): boolean {
+  const sLen = s.length;
+
+  const dp: boolean[] = new Array(sLen + 1).fill(false);
+  dp[0] = true;
+
+  const trie = new Trie();
+
+  for (const word of wordDict) {
+    trie.insert(word);
+  }
+
+  for (let i = 1; i <= sLen; i++) {
+    for (let j = 0; j < i; j++) {
+      if (dp[j]) {
+        if (trie.search(s.substring(j, i))) {
+          dp[i] = true;
+          break;
+        }
+      }
+    }
+  }
+
+  return dp[sLen];
+}