add: word search

Author: Yongseok-Choi-dev

word-search/YoungSeok-Choi.java

@@ -0,0 +1,120 @@
+// NOTE: Queue를 처음에 써서 탐색하며 꼬여버리는 문제가 있었다..
+// NOTE: 원본 문자의 index를 사용해서 해결.
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+class Solution {
+
+    public boolean[][] visit;
+    int w = 0;
+    int h = 0;
+    int[] dx = {1, 0, -1, 0};
+    int[] dy = {0, 1, 0, -1};
+    
+    public boolean exist(char[][] board, String word) {
+
+        char[] cArr = word.toCharArray();
+        w = board.length;
+        h = board[0].length;
+        visit = new boolean[w][h];
+        
+        for(int i = 0; i < board.length; i++) {
+            for(int j = 0; j < board[0].length; j++) {
+                if(cArr[0] == board[i][j]) {                   
+                    
+                    if(dfs(board, word, i, j, 0)) {
+                        return true;
+                    }
+                }
+            }
+        }
+
+        return false;
+    }
+
+    public boolean dfs(char[][] b, String word, int x, int y, int idx) {
+        if(idx == word.length()) return true;
+        
+        if(x < 0 || x >= w || y < 0 || y >= h || b[x][y] != word.charAt(idx) || visit[x][y]) {
+            return false;
+        }
+
+        visit[x][y] = true;
+
+        for(int i = 0; i < 4; i++) {
+            int nx = x + dx[i];
+            int ny = y + dy[i];
+
+            if(dfs(b, word, nx, ny, idx + 1)) {
+                return true;
+            }
+        }
+
+        visit[x][y] = false;
+        return false;
+    }
+    
+    
+    
+    class WrongSolution {
+
+        public boolean[][] visit;
+        Queue<Character> q = new LinkedList();
+        int w = 0;
+        int h = 0;
+        int[] dx = {1, 0, -1, 0};
+        int[] dy = {0, 1, 0, -1};
+        
+        public boolean exist(char[][] board, String word) {
+    
+            char[] cArr = word.toCharArray();
+            w = board.length;
+            h = board[0].length;
+            visit = new boolean[w][h];
+            
+            for(int i = 0; i < board.length; i++) {
+                for(int j = 0; j < board[0].length; j++) {
+                    if(cArr[0] == board[i][j]) {
+                        q = new LinkedList();
+                        visit = new boolean[w][h];
+                        for(char c : word.toCharArray()) {
+                            q.add(c);
+                        }
+    
+    
+                        dfs(board, i, j);
+                        if(q.isEmpty()) {
+                            return true;
+                        }
+                    }
+                }
+            }
+    
+            return false;
+        }
+    
+        public void dfs(char[][] b, int x, int y) {
+            if(x < 0 || x >= w || y < 0 || y >= h || visit[x][y]) {
+                return;
+            }
+    
+            if(q.isEmpty()) {
+                return;
+            }
+    
+            if(b[x][y] != q.peek()) {
+                return;
+            }
+    
+            q.poll();
+            visit[x][y] = true;
+            
+            for(int i = 0; i < 4; i++) {
+                int nx = x + dx[i];
+                int ny = y + dy[i];
+    
+                dfs(b, nx, ny);
+            }
+        }
+    }}