add: 문자사전

Author: Yongseok-Choi-dev

design-add-and-search-words-data-structure/YoungSeok-Choi.java

@@ -0,0 +1,170 @@
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+
+// NOTE: dot에 대한 wildcard 검색이 핵심이었던 문제.
+// NOTE: tc -> 문자 입력 O(n), 패턴검색 O(26^n), 패턴X검색 O(1)
+
+/** 
+  검색어    | 의미
+    "."    |  길이가 1인 아무 문자와 매치
+    ".a"   |  길이 2: 첫 글자는 아무 문자, 두 번째는 a
+    "..d"  |  길이 3: 처음 두 글자는 아무 문자, 마지막은 d
+    "..."  |  길이 3인 모든 단어와 매치
+*/ 
+class WordDictionary {
+
+    private WordDictionary[] child;
+    private Character val;
+    private Map<String, Boolean> cMap;
+
+    public WordDictionary() {
+         this.cMap = new HashMap<>();
+        this.val = null;
+    }
+    
+    public void addWord(String word) {
+        if(this.cMap.containsKey(word)) return;
+
+        this.cMap.put(word, true);
+        this.innerInsert(word);
+    }
+
+    public void innerInsert(String word) {
+        if(word.length() == 0) return;
+
+        if(this.child == null) {
+            this.child = new WordDictionary[26];
+        }
+        
+        char c = word.charAt(0);
+        int idx = c - 97;
+    
+        if(this.child[idx] == null) {
+            this.child[idx] = new WordDictionary();
+            this.child[idx].val = c;
+        }
+
+        this.child[idx].innerInsert(word.substring(1));
+    }
+    
+    public boolean search(String word) {
+        if(!word.contains(".")) return this.cMap.containsKey(word);
+
+
+        return this.patternSearch(word);
+    }
+
+    private boolean patternSearch(String wildcard) {
+        if(wildcard.length() == 0) return true;
+
+        char c = wildcard.charAt(0);
+        if(c == '.') { // NOTE: wildcard를 만났을 때, 해당 depth는 검사하지 않고, 다음 번(자식) 문자들에 대해서 검색 이어나가기.
+            List<Boolean> res = new ArrayList<>();
+
+            for(WordDictionary children : this.child) {
+                if(children != null) {
+                    res.add(children.patternSearch(wildcard.substring(1)));
+                }
+            }
+
+            for(boolean b : res) {
+                if(b) return true;
+            }
+
+            return false;
+        } 
+        
+        int idx = c - 97;
+        if(this.child == null || this.child[idx] == null || this.child[idx].val == null) return false;
+
+        return this.child[idx].patternSearch(wildcard.substring(1));
+    }
+}
+
+/**
+ * Your WordDictionary object will be instantiated and called as such:
+ * WordDictionary obj = new WordDictionary();
+ * obj.addWord(word);
+ * boolean param_2 = obj.search(word);
+ */
+
+
+// 이전 TRIE 자료구조를 모른 채로 풀이했던 문제..
+class PrevWordDictionary {
+
+    private String word;
+    private PrevWordDictionary leftChild;
+    private PrevWordDictionary rightChild;
+
+    public PrevWordDictionary() {
+        this.leftChild = null;
+        this.rightChild = null;
+        this.word = null;
+    }
+    
+    public void addWord(String word) {
+        if(this.word == null) {
+            this.word = word;
+            return;
+        }
+
+        // NOTE: 사전 순으로 크고 작음을 두어 이진처리.
+        if(this.word.compareTo(word) == 1) {
+
+            this.rightChild = new PrevWordDictionary();
+            this.rightChild.addWord(word);
+        } else if (this.word.compareTo(word) == -1) {
+
+            this.leftChild = new PrevWordDictionary();
+            this.leftChild.addWord(word);
+        } else {
+            // already exists. just return
+        }
+    }
+    
+    public boolean search(String word) {
+        if(word.contains(".")) {
+            //  String replaced = word.replace(".", "");
+
+            // return word.startsWith(".") ? this.startsWith(replaced) : this.endsWith(replaced);           
+            return this.patternSearch(word.replace(".", ""));
+        }
+
+        if(this.word == null) {
+            return false;
+        }
+
+        if(this.word.equals(word)) {
+            return true;
+        }
+
+        if(this.rightChild == null && this.leftChild == null) {
+            return false;
+        }
+
+        if(this.word.compareTo(word) == 1) {
+            return this.rightChild == null ? false : this.rightChild.search(word);
+        } else {
+            return this.leftChild == null ? false : this.leftChild.search(word);
+        }
+    }
+
+    private boolean patternSearch(String wildcard) {
+        if(this.word.contains(wildcard)) return true;
+        
+        boolean left = false;
+        boolean right = false;
+        if(this.leftChild != null) {
+           left = this.leftChild.patternSearch(wildcard);
+        }
+
+        if(this.rightChild != null) {
+           right = this.rightChild.patternSearch(wildcard);
+        }
+
+        return left || right;
+    }
+}