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227124b327
problems(cs): add „637. Average of Levels in Binary Tree“
Signed-off-by: Matej Focko <mfocko@redhat.com>

diff --git a/problems/average-of-levels-in-binary-tree.cs b/problems/average-of-levels-in-binary-tree.cs
new file mode 100644
index 0000000..f2ba5aa
--- /dev/null
+++ b/problems/average-of-levels-in-binary-tree.cs
@@ -0,0 +1,72 @@
+public class TreeNode
+{
+    public int val;
+    public TreeNode? left;
+    public TreeNode? right;
+    public TreeNode(int val = 0, TreeNode? left = null, TreeNode? right = null)
+    {
+        this.val = val;
+        this.left = left;
+        this.right = right;
+    }
+}
+
+
+public class Solution
+{
+    private class Level
+    {
+        long sum;
+        int counter;
+
+        public Level()
+        {
+            sum = 0;
+            counter = 0;
+        }
+
+        public void Add(int x)
+        {
+            sum += x;
+            counter++;
+        }
+
+        public double Average
+        {
+            get => sum / (double)counter;
+        }
+    }
+
+    private List<Level> AverageOfLevels(List<Level> averages, TreeNode? node, int level)
+    {
+        if (node == null)
+        {
+            return averages;
+        }
+
+        if (level == averages.Count)
+        {
+            averages.Add(new Level());
+        }
+        averages[level].Add(node.val);
+
+        AverageOfLevels(averages, node.left, level + 1);
+        AverageOfLevels(averages, node.right, level + 1);
+
+        return averages;
+    }
+
+    public IList<double> AverageOfLevels(TreeNode? root)
+        => AverageOfLevels(new List<Level>(), root, 0).Select(level => level.Average).ToList();
+
+    public static void Main()
+    {
+        var s = new Solution();
+
+        foreach (var a in s.AverageOfLevels(new TreeNode(3, new TreeNode(9), new TreeNode(20, new TreeNode(15), new TreeNode(7)))))
+        {
+            Console.Write($"{a} ");
+        }
+        Console.WriteLine();
+    }
+}
2022-09-02 21:11:03 +02:00