[gyim1345] Trie 구현

자료구조/Trie.test.js

@@ -0,0 +1,141 @@
+class Node {
+  constructor() {
+    this.keys = new Map();
+    this.end = false;
+  }
+
+  setEnd() {
+    this.end = true;
+  };
+
+  isEnd() {
+    return this.end;
+  };
+}
+
+class Trie {
+  constructor() {
+    this.root = new Node();  
+  }
+
+  add(input, currentNode = this.root) {
+    if(input.length === 0) {
+      currentNode.setEnd();
+      return;
+    }
+    const currentLetter = input[0];
+    const nextLetterNode = currentNode.keys.get(currentLetter) || new Node();
+
+    if(!currentNode.keys.has(currentLetter)) {
+      currentNode.keys.set(currentLetter, nextLetterNode);
+    }
+
+    return this.add(input.substring(1), nextLetterNode);
+  }
+
+  getWords(input) {
+    const words = [];
+    const startNode = this.getStartNode(input);
+
+    if(startNode === 'not found') {
+      return startNode;
+    }
+    this.dfs(startNode, words, input)
+    return words;
+  }
+
+  getStartNode(input) {
+    if(!input) {
+      return this.root;
+    }
+
+    let count = 0;
+    let currentNode = this.root;
+
+    while(input.length > count) {
+      if(!currentNode.keys.has(input[count])) {
+        return 'not found';
+      }
+      currentNode = currentNode.keys.get(input[count]);
+      count += 1;
+    }
+
+    return currentNode;
+  };
+
+  dfs(currentNode, results, input = '', currentWord = '') {
+    if(currentNode.length === 0) {
+      return;
+    }
+
+    if(currentNode.isEnd()) {
+      results.push(input + currentWord);
+    }
+
+    currentNode.keys.forEach((node, currentLetter) => {
+      this.dfs(node, results, input, currentWord + currentLetter);
+    })
+  }
+
+  isWord(input) {
+    const node = this.getStartNode(input);
+    if(node === 'not found') {
+      return false;
+    } 
+    return node.end;
+  }
+};
+
+describe('Trie', () => {
+  beforeEach(() => {
+    newTrie = new Trie()
+    newTrie.add('ball'); 
+    newTrie.add('bat'); 
+    newTrie.add('doll'); 
+    newTrie.add('dork'); 
+    newTrie.add('do'); 
+    newTrie.add('dorm')
+    newTrie.add('send')
+    newTrie.add('sense')
+  })
+
+  describe('getWords', () => {
+    it('returns matching words', () => {
+      expect(newTrie.getWords()).toEqual(
+        [
+          'ball', 'bat',
+          'do',   'doll',
+          'dork', 'dorm',
+          'send', 'sense'
+        ]
+      );
+      expect(newTrie.getWords('ba')).toEqual(
+        [
+          'ball', 'bat'
+        ]
+      );
+      expect(newTrie.getWords('s')).toEqual(
+        [
+          'send', 'sense'
+        ]
+      );
+      expect(newTrie.getWords('doll')).toEqual(
+        [
+          'doll'
+        ]
+      );
+      expect(newTrie.getWords('dolla')).toBe(
+        'not found'
+      );
+    });
+  });
+
+  describe('isWord', () => {
+    it('checks word existence and validity', () => {
+      expect(newTrie.isWord('')).toBe(false);
+      expect(newTrie.isWord('doll')).toBe(true)
+      expect(newTrie.isWord('dor')).toBe(false)
+      expect(newTrie.isWord('dorf')).toBe(false)
+    });
+  });
+})