Day8-9

200. Number of Islands/200. Number of Islands.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_200._Number_of_Islands</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

200. Number of Islands/Program.cs

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+namespace _200._Number_of_Islands;
+
+internal class Program
+{
+    static void Main(string[] args)
+    {
+        Console.WriteLine("Hello, World!");
+    }
+}

200. Number of Islands/Solution.cs

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+using System.ComponentModel;
+
+namespace _200._Number_of_Islands;
+
+public class Solution
+{
+    public int NumIslands(char[][] grid)
+    {
+        int[][] was = new int[grid.Length][];
+        for (int i = 0; i < grid.Length; i++)
+            was[i] = new int[grid[i].Length];
+
+        int curId = 0;
+        for (int y = 0; y < grid.Length; y++)
+        {
+            for (int x = 0; x < grid[y].Length; x++)
+            {
+                if (was[y][x] == 0 && grid[y][x] == '1')
+                    curId++;
+                else
+                    continue;
+
+                Recursion(grid, was, y, x, curId);
+            }
+        }
+        return curId;
+    }
+
+    private void Recursion(char[][] grid, int[][] was, int y, int x, int id)
+    {
+        if (was[y][x]!=0 || grid[y][x] != '1')
+            return;
+        was[y][x] = id;
+        for (int i = 1; i < 8; i += 2)
+        {
+            int nextY = i / 3 + y - 1;
+            int nextX = i % 3 + x - 1;
+            if (nextY >= 0 && nextY < was.Length && nextX >= 0 && nextX < was[nextY].Length)
+                Recursion(grid, was, nextY, nextX, id);
+        }
+    }
+}