word search

Author: eunhwa99

word-search/eunhwa99.java

@@ -0,0 +1,43 @@
+class Solution {
+
+  // 시간 복잡도: O(m * n * 4^L) - m: 행, n: 열, L: 단어 길이
+  // 공간 복잡도: O(m * n) - 방문 체크를 위한 공간
+  public boolean exist(char[][] board, String word) {
+    int rows = board.length;
+    int cols = board[0].length;
+
+    for (int r = 0; r < rows; r++) {
+      for (int c = 0; c < cols; c++) {
+        if (dfs(board, word, 0, r, c)) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+
+  private boolean dfs(char[][] board, String word, int index, int r, int c) {
+    if (index == word.length()) {
+      return true;
+    }
+
+    if (r < 0 || r >= board.length || c < 0 || c >= board[0].length || board[r][c] != word.charAt(
+        index)) {
+      return false;
+    }
+
+    char temp = board[r][c];
+    board[r][c] = '#';
+
+    boolean found =
+        dfs(board, word, index + 1, r + 1, c) ||
+            dfs(board, word, index + 1, r - 1, c) ||
+            dfs(board, word, index + 1, r, c + 1) ||
+            dfs(board, word, index + 1, r, c - 1);
+
+    board[r][c] = temp;
+    return found;
+  }
+}
+