From cfa3baf2539c7790eb973113a94b8910372fe89d Mon Sep 17 00:00:00 2001
From: Masahiko AMANO <hiko-19@yandex.com>
Date: Wed, 2 Mar 2022 23:05:47 +0300
Subject: [PATCH] Recursive opening of empty cells

---
 Field.cs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Field.cs b/Field.cs
index 13abc93..034ef2c 100644
--- a/Field.cs
+++ b/Field.cs
@@ -95,8 +95,27 @@
             if (y < 0 || y >= height || x < 0 || x >= width)
                 throw new Exception("Coordinates out of the field!");
             cells[y * width + x].open();
+            if (cells[y * width + x].isEmpty())
+                this.recur_open(y, x, new List<Cell>());
             return cells[y * width + x].isMine;
         }
+        private void recur_open(int y, int x, List<Cell> opened)
+        {
+            if (!cells[y * width + x].isMine)
+                cells[y * width + x].open();
+            if (cells[y * width + x].isEmpty() && !opened.Contains(cells[y * width + x]))
+            {
+                opened.Add(cells[y * width + x]);
+                if (x < width - 1)
+                    this.recur_open(y, x + 1, opened);
+                if (x > 0)
+                    this.recur_open(y, x - 1, opened);
+                if (y < height - 1)
+                    this.recur_open(y + 1, x, opened);
+                if (y > 0)
+                    this.recur_open(y - 1, x, opened);
+            }
+        }
         public void openall()
         {
             for (int i = 0; i < size; i++)