word search

Author: se6816

word-search/se6816.java

@@ -0,0 +1,73 @@
+
+/**
+    DFS를 통해 이중 배열에서 문자를 찾는 방식
+    board의 길이 -> M
+    board[i]의 길이 -> N
+    시간 복잡도 : O(M*N)
+    공간 복잡도 : O(M*N)
+ */
+class Solution {
+    public static int[] moveX = {0, -1, 1, 0};
+    public static int[] moveY = {-1, 0, 0, 1};
+    public int N;
+    public int M;
+    public boolean exist(char[][] board, String word) {
+        M = board.length;
+        N = board[0].length;
+        boolean result = false;
+        char startCh = word.charAt(0);
+        for(int i = 0; i < M; i++) {
+            for(int j = 0; j < N; j++) {
+                if(board[i][j] != startCh) {
+                    continue;
+                }
+                boolean[][] visited = new boolean[M][N];
+                visited[i][j] = true;
+                result = result || search(board, visited, i, j, 1, word);
+            }
+        }
+        return result;
+    }
+
+    public boolean search(char[][] board, boolean[][] visited, int x, int y, int len, String target) {
+        if(len >= target.length()) {
+            return true;
+        }
+
+        boolean result = false;
+
+        for(int i = 0; i < 4; i++) {
+            int tempX = x + moveX[i];
+            int tempY = y + moveY[i];
+
+            if(outOfIndex(tempX, tempY)) {
+                continue;
+            }
+
+            if(visited[tempX][tempY]) {
+                continue;
+            }
+
+            if(board[tempX][tempY] != target.charAt(len)) {
+                continue;
+            }
+
+            visited[tempX][tempY] = true;
+            result = search(board, visited, tempX, tempY, len + 1, target) || result;
+            if(result) {
+                break;
+            }
+            visited[tempX][tempY] = false;
+        }
+
+        return result;
+    }
+
+    public boolean outOfIndex(int x, int y){
+        if(x < 0 || x >= M || y < 0 || y >= N) {
+            return true;
+        }
+
+        return false;
+    }
+}