trie 구현 연습

Author: hyeonbinHur

허현빈/8주차/trie-구현-1.js

@@ -0,0 +1,113 @@
+// @ts-nocheck
+
+class TrieNode {
+  constructor() {
+    this.children = new Map();
+    this.pass = 0;
+    this.end = 0;
+  }
+}
+
+class Trie {
+  constructor() {
+    this.root = new TrieNode();
+    this.totalWorlds = 0;
+  }
+  insert(word) {
+    let node = this.root;
+    node.pass++;
+
+    for (let i = 0; i < word.length; i++) {
+      const ch = word[i];
+      if (!node.children.has(ch)) {
+        node.children.set(ch, new TrieNode());
+      }
+      node = node.children.get(ch);
+      node.pass++;
+    }
+    node.end++;
+    this.totalWorlds = word.length;
+  }
+
+  #walk(s) {
+    let node = this.root;
+    for (let i = 0; i < s.length; i++) {
+      const ch = s[i];
+      const next = node.children.get(ch);
+      if (!next) return null;
+
+      node = next;
+    }
+    return node;
+  }
+
+  search(s) {
+    const node = this.#walk(s);
+    return !!node && node.end > 0;
+  }
+
+  countWordsEqualTo(s) {
+    const node = this.#walk(s);
+    return node ? node.end : 0;
+  }
+
+  startsWith(s) {
+    const node = this.#walk(s);
+    return node ? node.pass : 0;
+  }
+
+  delete(s) {
+    if (!this.search(s)) return false;
+    let node = this.root;
+    node.pass--;
+    const stack = [];
+    for (let i = 0; i < s.length; i++) {
+      const ch = s[i];
+      stack.push([node, ch]);
+      node = node.children.get(ch);
+      node.pass--;
+    }
+    node.end--;
+    this.totalWorlds--;
+    for (let i = stack.length - 1; i >= 0; i--) {
+      const [par, ch] = stack[i];
+      const child = par.children.get(ch);
+      if (child.pass === 0) par.children.delete(ch);
+      else break;
+    }
+    return true;
+  }
+
+  words() {
+    const res = [];
+    const path = [];
+
+    const dfs = (node) => {
+      if (node.end > 0) {
+        res.push(path.join(""));
+      }
+      for (const [ch, next] of node.children) {
+        path.push(ch);
+        dfs(next);
+        path.pop();
+      }
+    };
+
+    dfs(this.root);
+    return res;
+  }
+}
+const trie = new Trie();
+
+trie.insert("flower");
+trie.insert("flow");
+trie.insert("flight");
+trie.insert("flow"); // duplicate
+
+console.log(trie.search("flow")); // true
+console.log(trie.countWordsEqualTo("flow")); // 2
+console.log(trie.startsWith("fl")); // true
+
+trie.delete("flow");
+console.log(trie.countWordsEqualTo("flow")); // 1
+console.log(trie.words()); // unique words: ["flower","flow","flight"] (again order may vary)

허현빈/8주차/trie-구현.js

@@ -0,0 +1,135 @@
+// @ts-nocheck
+
+class TrieNode {
+  constructor() {
+    this.children = new Map();
+    this.pass = 0;
+    this.end = 0;
+  }
+}
+
+class Trie {
+  constructor() {
+    this.root = new TrieNode();
+    this.totalWords = 0;
+  }
+
+  insert(word) {
+    if (typeof word !== "string") throw new TypeError("word must be a string");
+    let node = this.root;
+    node.pass++;
+
+    for (const ch of word) {
+      if (!node.children.has(ch)) node.children.set(ch, new TrieNode());
+      node = node.children.get(ch);
+      node.pass++;
+    }
+    node.end++;
+    this.totalWords++;
+  }
+
+  search(word) {
+    const node = this.#walk(word);
+    return !!node && node.end > 0;
+  }
+
+  startsWith(prefix) {
+    return !!this.#walk(prefix);
+  }
+
+  countWordsEqualTo(word) {
+    const node = this.#walk(word);
+    return node ? node.end : 0;
+  }
+
+  countWordsStartingWith(prefix) {
+    const node = this.#walk(prefix);
+    return node ? node.pass : 0;
+  }
+
+  delete(word) {
+    if (!this.search(word)) return false;
+
+    let node = this.root;
+    node.pass--;
+
+    const stack = [];
+    for (const ch of word) {
+      stack.push([node, ch]);
+      node = node.children.get(ch);
+      node.pass--;
+    }
+
+    node.end--;
+    this.totalWords--;
+
+    for (let i = stack.length - 1; i >= 0; i--) {
+      const [parent, ch] = stack[i];
+      const child = parent.children.get(ch);
+      if (child.pass === 0) parent.children.delete(ch);
+      else break;
+    }
+    return true;
+  }
+
+  words() {
+    const res = [];
+    const path = [];
+
+    const dfs = (node) => {
+      if (node.end > 0) res.push(path.join(""));
+      for (const [ch, nxt] of node.children) {
+        path.push(ch);
+        dfs(nxt);
+        path.pop();
+      }
+    };
+
+    dfs(this.root);
+    return res;
+  }
+
+  longestCommonPrefix() {
+    if (this.totalWords === 0) return "";
+
+    let node = this.root;
+    let prefix = "";
+
+    while (node.children.size === 1 && node.end === 0) {
+      const [[ch, next]] = node.children.entries();
+      prefix += ch;
+      node = next;
+    }
+    return prefix;
+  }
+
+  #walk(s) {
+    let node = this.root;
+    for (const ch of s) {
+      const nxt = node.children.get(ch);
+      if (!nxt) return null;
+      node = nxt;
+    }
+    return node;
+  }
+}
+
+const trie = new Trie();
+
+trie.insert("flower");
+trie.insert("flow");
+trie.insert("flight");
+trie.insert("flow"); // duplicate
+
+console.log(trie.search("flow")); // true
+console.log(trie.countWordsEqualTo("flow")); // 2
+console.log(trie.startsWith("fl")); // true
+console.log(trie.countWordsStartingWith("flo")); // 3 ("flower","flow","flow")
+
+console.log(trie.autocomplete("fl", { limit: 10 })); // e.g. ["flight","flow","flower"] (order depends on insertion/Map order)
+console.log(trie.searchWithWildcard("fl..")); // true ("flow")
+console.log(trie.longestCommonPrefix()); // "fl"
+
+trie.delete("flow");
+console.log(trie.countWordsEqualTo("flow")); // 1
+console.log(trie.words()); // unique words: ["flower","flow","flight"] (again order may vary)