trie 구현

Author: hyeonbinHur

허현빈/8주차/trie-구현-1.js 허현빈/8주차/trie/trie-구현-1.js허현빈/8주차/trie-구현-1.js renamed to 허현빈/8주차/trie/trie-구현-1.js

@@ -1,7 +1,8 @@
 // @ts-nocheck
 
 class TrieNode {
-  constructor() {
+  constructor(value = "") {
+    this.value = value;
     this.children = new Map();
     this.pass = 0;
     this.end = 0;
@@ -10,34 +11,39 @@ class TrieNode {
 
 class Trie {
   constructor() {
-    this.root = new TrieNode();
-    this.totalWorlds = 0;
+    this.root = new TrieNode("");
+    this.totalWords = 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.children.set(ch, new TrieNode(node.value + ch));
       }
+
       node = node.children.get(ch);
       node.pass++;
     }
+
     node.end++;
-    this.totalWorlds = word.length;
+    this.totalWords++;
   }
 
   #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;
   }
 
@@ -50,31 +56,36 @@ class Trie {
     const node = this.#walk(s);
     return node ? node.end : 0;
   }
-
-  startsWith(s) {
-    const node = this.#walk(s);
+  countWordsStartingWith(prefix) {
+    const node = this.#walk(prefix);
     return node ? node.pass : 0;
   }
 
-  delete(s) {
-    if (!this.search(s)) return false;
+  delete(word) {
+    if (!this.search(word)) return false;
+
     let node = this.root;
     node.pass--;
+
     const stack = [];
-    for (let i = 0; i < s.length; i++) {
-      const ch = s[i];
+    for (let i = 0; i < word.length; i++) {
+      const ch = word[i];
       stack.push([node, ch]);
+
       node = node.children.get(ch);
       node.pass--;
     }
+
     node.end--;
-    this.totalWorlds--;
+    this.totalWords--;
+
     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;
   }
 
@@ -86,7 +97,13 @@ class Trie {
       if (node.end > 0) {
         res.push(path.join(""));
       }
-      for (const [ch, next] of node.children) {
+
+      const entries = Array.from(node.children.entries());
+
+      for (let i = 0; i < entries.length; i++) {
+        const ch = entries[i][0];
+        const next = entries[i][1];
+
         path.push(ch);
         dfs(next);
         path.pop();
@@ -97,6 +114,7 @@ class Trie {
     return res;
   }
 }
+
 const trie = new Trie();
 
 trie.insert("flower");
@@ -106,8 +124,8 @@ 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("fl")); // 4 (flower, flow, flight, flow)
 
 trie.delete("flow");
 console.log(trie.countWordsEqualTo("flow")); // 1
-console.log(trie.words()); // unique words: ["flower","flow","flight"] (again order may vary)
+console.log(trie.words()); // ["flight","flow","flower"] (순서는 Map 순서에 따라 달라질 수 있음)

허현빈/8주차/trie/trie-구현-2.js

@@ -0,0 +1,106 @@
+// @ts-nocheck
+class TrieNode {
+  constructor(val = "") {
+    this.val = val;
+    this.children = new Map();
+    this.pass = 0;
+    this.isEnd = false;
+  }
+}
+class Trie {
+  constructor() {
+    this.root = new TrieNode("");
+    this.totalWords = 0;
+  }
+
+  insert(s) {
+    let node = this.root;
+    node.pass++;
+    for (let i = 0; i < s.length; i++) {
+      const ch = s[i];
+      if (!node.children.get(ch)) {
+        node.children.set(ch, new TrieNode(ch));
+      }
+      node = node.children.get(ch);
+      node.pass++;
+    }
+    node.isEnd = true;
+    this.totalWords = s.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.isEnd === true;
+  }
+  startWith(s) {
+    const node = this.#walk(s);
+    return node ? node.pass : 0;
+  }
+
+  delete(s) {
+    if (!this.search(s)) return false;
+    let node = this.root;
+    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.isEnd = false;
+    this.totalWords--;
+
+    for (let i = stack.length - 1; i >= 0; i--) {
+      const [par, ch] = stack[i];
+      const child = par.children.get(cj);
+      if (child.pass === 0) par.children.delete(child);
+      else break;
+    }
+
+    return true;
+  }
+
+  words() {
+    const res = [];
+    const path = [];
+    const dfs = (node) => {
+      if (node.isEnd) {
+        res.push(path.join(""));
+      }
+      const entries = Array.from(node.children.entries());
+      for (let i = 0; i < entries.length; i++) {
+        const ch = entries[i][0];
+        const next = entries[i][1];
+        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.startWith("fl")); // 4 (flower, flow, flight, flow)
+
+console.log(trie.words()); // ["flight","flow","flower"] (순서는 Map 순서에 따라 달라질 수 있음)

허현빈/8주차/trie/trie-구현-3.js

@@ -0,0 +1 @@
+// @ts-nocheck

허현빈/8주차/trie/trie-구현-4.js

@@ -0,0 +1 @@
+