[20251114] PGM / Lv3 / 단어 변환 / 이강현

Author: lkhyun

lkhyun/202511/14 PGM Lv3 단어 변환.md

@@ -0,0 +1,51 @@
+```java
+class Solution {
+    static int answer;
+    static boolean[] visited;
+    
+    public int solution(String begin, String target, String[] words) {
+        boolean hasTarget = false;
+        for(String word : words) {
+            if(word.equals(target)) {
+                hasTarget = true;
+                break;
+            }
+        }
+        if(!hasTarget) return 0;
+        
+        answer = Integer.MAX_VALUE;
+        visited = new boolean[words.length];
+        DFS(begin, target, words, 0);
+        
+        return answer == Integer.MAX_VALUE ? 0 : answer;
+    }
+    
+    public static void DFS(String from, String target, String[] words, int depth){
+        if(target.equals(from)){
+            answer = Math.min(answer, depth);
+            return;
+        }
+        
+        for(int i = 0; i < words.length; i++){
+            if(visited[i]) continue;
+            
+            if(isOneDifferent(from, words[i])){
+                visited[i] = true;
+                DFS(words[i], target, words, depth + 1);
+                visited[i] = false;
+            }
+        }
+    }
+    
+    private static boolean isOneDifferent(String word1, String word2) {
+        int diff = 0;
+        for(int i = 0; i < word1.length(); i++){
+            if(word1.charAt(i) != word2.charAt(i)){
+                diff++;
+                if(diff > 1) return false;
+            }
+        }
+        return diff == 1;
+    }
+}
+```