word-search

Author: chjung99

word-search/chjung99.java

@@ -0,0 +1,50 @@
+class Solution {
+    int m, n;
+    int[] dx = new int[]{0, 1, 0, -1};
+    int[] dy = new int[]{1, 0, -1, 0};
+    boolean answer = false;
+    boolean[][] visit;
+
+    public boolean exist(char[][] board, String word) {
+        m = board.length;
+        n = board[0].length;
+        visit = new boolean[m][n];
+
+        for (int i = 0; i < m; i++){
+            for (int j = 0; j < n; j++){
+                if (board[i][j] == word.charAt(0)){
+                    visit[i][j] = true;
+                    dfs(i, j, board, word, 0);
+                    visit[i][j] = false;
+                }
+            }
+        }
+        return answer;
+    }
+
+    public void dfs(int cx, int cy, char[][] board, String word, int depth){
+        if (depth == word.length()-1){
+            answer = true;
+            return;
+        }
+
+        for (int i = 0; i < 4; i++){
+            int nx = cx + dx[i];
+            int ny = cy + dy[i];
+            int nextDepth = depth + 1;
+
+            if (outOfRange(nx, ny)||visit[nx][ny]) continue;
+            if (board[nx][ny] == word.charAt(nextDepth)){
+                visit[nx][ny] = true;
+                dfs(nx, ny, board, word, nextDepth);
+                visit[nx][ny] = false;
+            }
+        }
+    }
+
+    public boolean outOfRange(int x, int y){
+        return (x < 0 || x >= m) || (y < 0 || y >= n);
+    }
+}
+
+