From 43bcd24b2d47ff9b60eccedf7a6bb89c44b38cc4 Mon Sep 17 00:00:00 2001
From: Matej Focko <mfocko@redhat.com>
Date: Sat, 6 Apr 2024 00:05:24 +0200
Subject: [PATCH] =?UTF-8?q?cs:=20add=20=C2=AB79.=20Word=20Search=C2=BB?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Matej Focko <mfocko@redhat.com>
---
 cs/word-search.cs | 55 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 cs/word-search.cs

diff --git a/cs/word-search.cs b/cs/word-search.cs
new file mode 100644
index 0000000..80064f9
--- /dev/null
+++ b/cs/word-search.cs
@@ -0,0 +1,55 @@
+public class Solution {
+    private struct Solver {
+        char[][] Board { get; init; }
+        int Height { get => Board.Length; }
+        int Width { get => Board[0].Length; }
+
+        string Word { get; init; }
+
+        public Solver(char[][] board, string word) {
+            Board = board;
+            Word = word;
+        }
+
+        private bool Has(int y, int x)
+            => y >= 0 && y < Height && x >= 0 && x < Width;
+
+        private bool DFS(int y, int x, int i) {
+            if (i == Word.Length) {
+                return true;
+            }
+
+            if (!Has(y, x) || Board[y][x] == '!' || Word[i] != Board[y][x]) {
+                return false;
+            }
+
+            var tmp = Board[y][x];
+            Board[y][x] = '!';
+
+            foreach (int d in new int[] { 1, -1 }) {
+                if (DFS(y + d, x, i + 1) || DFS(y, x + d, i + 1)) {
+                    return true;
+                }
+            }
+
+            Board[y][x] = tmp;
+            return false;
+        }
+
+        public bool Solve() {
+            for (int y = 0; y < Height; ++y) {
+                for (int x = 0; x < Width; ++x) {
+                    if (DFS(y, x, 0)) {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+    }
+
+    public bool Exist(char[][] board, string word) {
+        return new Solver(board, word).Solve();
+    }
+}