design add and search words data structure

Author: se6816

design-add-and-search-words-data-structure/se6816.java

@@ -0,0 +1,116 @@
+/**
+	Tries + BFS를 활용한 방식
+	addWord()
+	문자열 word의 길이 -> N
+	시간 복잡도 : O(N) 
+	공간 복잡도 : O(N)
+	search()
+	Tries 내부의 노드 개수 -> M
+	시간 복잡도 : O(M)
+	공간 복잡도 : O(M)
+*/
+class WordDictionary {
+    public Map<Character, WordNode> wordMap;
+
+    public WordDictionary() {
+        wordMap = new HashMap<>();
+    }
+    
+    public void addWord(String word) {
+        WordNode wordNode = null;
+        char ch = word.charAt(0);
+        wordNode = wordMap.get(ch);
+
+        if(wordNode == null) {
+            boolean isFirstWord = word.length() == 1;
+            wordNode = new WordNode(ch, isFirstWord);
+            wordMap.put(ch, wordNode);
+        }
+
+        for(int idx = 1; idx < word.length(); idx++) {
+            char target = word.charAt(idx);
+            boolean isLeaf = word.length() - 1 == idx;
+            wordNode = wordNode.next.computeIfAbsent(target, key -> new WordNode(key, isLeaf));
+        }
+        wordNode.isLeaf = true;
+        
+        
+    }
+    
+    public boolean search(String word) {
+        Queue<Node> que = new ArrayDeque<>();
+        boolean result = false;
+        char ch = word.charAt(0);
+        WordNode wordNode = wordMap.get(ch);
+        int len = word.length();
+
+        if(ch == '.' && wordMap.size() != 0) {
+            for(Map.Entry<Character, WordNode> entry : wordMap.entrySet()) {
+                que.add(new Node(entry.getValue(), 1));
+            }
+        }
+
+        if (wordNode != null) {
+            que.add(new Node(wordNode, 1));
+        }
+
+
+
+        while(!que.isEmpty()) {
+            Node node = que.poll();
+            if(node.idx == len && node.wordNode.isLeaf) {
+                result = true;
+                break;
+            }
+
+            if(node.idx == len) {
+                continue;
+            }
+
+            char target = word.charAt(node.idx);
+
+            if(target == '.' && node.wordNode.next.size() != 0) {
+                for(Map.Entry<Character, WordNode> entry : node.wordNode.next.entrySet()) {
+                    que.add(new Node(entry.getValue(), node.idx + 1));
+                }
+                continue;
+            }
+
+
+            if (!node.wordNode.next.containsKey(target)) {
+                continue;
+            }
+
+            que.add(new Node(node.wordNode.next.get(target), node.idx + 1));
+        }
+
+        return result;
+        
+    }
+}
+
+class Node {
+    WordNode wordNode;
+    int idx;
+    public Node(WordNode wordNode, int idx) {
+        this.wordNode = wordNode;
+        this.idx = idx;
+    }
+}
+
+class WordNode {
+    char ch;
+    Map<Character, WordNode> next;
+    boolean isLeaf;
+
+    public WordNode(char ch) {
+        this(ch, false);
+    }
+    
+    public WordNode(char ch, boolean isLeaf) {
+        next = new HashMap<>();
+        this.ch = ch;
+        this.isLeaf = isLeaf;
+    }
+
+}