DFS栈溢出真他妈无语

Author: h2pl

src/DFS/填充封闭区域.java

@@ -0,0 +1,72 @@
+package DFS;
+
+/**
+ * Created by 周杰伦 on 2018/3/31.
+ */
+public class 填充封闭区域 {
+    public static void main(String[] args) {
+
+    }
+    public void solve(char[][] board) {
+        if (board == null || board.length == 0)return;
+        int m = board.length;
+        int n = board[0].length;
+        if (m <= 2 || n <= 2)return;
+
+        int [][] visit = new int[m][n];
+        for (int i = 1;i < m - 1;i ++) {
+            for (int j = 1;j < n - 1;j ++) {
+                if (board[i][j] == 'O' && legal(board, i, j)) {
+                    dfs(board,visit,i,j);
+                }
+            }
+        }
+    }
+    public boolean dfs(char[][] board, int [][]visit, int x, int y) {
+        if (x < 0 || y < 0 || x >= board.length || y >= board[0].length) return false;
+        if (!legal(board, x, y)) return false;
+        if (board[x][y] == 'X') return true;
+        if (visit[x][y] == 1)return true;
+        visit[x][y] = 1;
+        if (x == 0 || y == 0 || x == board.length - 1 || y == board[0].length - 1)return false;
+        if (board[x - 1][y] == 'X' && board[x + 1][y] == 'X' && board[x][y - 1] == 'X' && board[x][y + 1] == 'X') {
+            board[x][y] = 'X';
+            return true;
+        }
+        boolean left = dfs(board,visit,x - 1,y);
+        if (!left) return false;
+        boolean right = dfs(board,visit,x + 1,y);
+        if (!right) return false;
+        boolean up = dfs(board,visit,x,y + 1);
+        if (!up) return false;
+        boolean down = dfs(board,visit,x,y - 1);
+        if (!down) return false;
+
+        board[x][y] = 'X';
+
+        return true;
+    }
+
+    public boolean legal (char [][]board, int x,int y) {
+        int count = 0;
+        for (int i = 0;i < y;i ++) {
+            if (board[x][i] == 'X') count ++;
+        }
+        if (count < 1)return false;
+        count = 0;
+        for (int i = y;i < board[0].length;i ++) {
+            if (board[x][i] == 'X') count ++;
+        }
+        if (count < 1)return false;
+        for (int i = 0;i < x;i ++) {
+            if (board[i][y] == 'X') count ++;
+        }
+        if (count < 1)return false;
+        for (int i = x;i < board.length;i ++) {
+            if (board[i][y] == 'X') count ++;
+        }
+        if (count < 1)return false;
+        return true;
+    }
+
+}