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Copy path0987-VerticalOrderTraversalOfABinaryTree.cs
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0987-VerticalOrderTraversalOfABinaryTree.cs
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//-----------------------------------------------------------------------------
// Runtime: 240ms
// Memory Usage: 30.9 MB
// Link: https://leetcode.com/submissions/detail/378620291/
//-----------------------------------------------------------------------------
using System.Collections.Generic;
using System.Linq;
namespace LeetCode
{
/**
* Definition for a binary tree node.
* 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 _0987_VerticalOrderTraversalOfABinaryTree
{
public IList<IList<int>> VerticalTraversal(TreeNode root)
{
var results = new List<IList<int>>();
if (root == null) return results;
var columnTable = new Dictionary<int, List<int>>();
var queue = new Queue<(int col, TreeNode node)>();
queue.Enqueue((0, root));
while (queue.Count > 0)
{
var size = queue.Count;
var levelColumnTable = new Dictionary<int, List<int>>();
for (int i = 0; i < size; i++)
{
(int col, TreeNode node) = queue.Dequeue();
if (!levelColumnTable.ContainsKey(col))
levelColumnTable[col] = new List<int>();
levelColumnTable[col].Add(node.val);
if (node.left != null)
queue.Enqueue((col - 1, node.left));
if (node.right != null)
queue.Enqueue((col + 1, node.right));
}
foreach (var pair in levelColumnTable)
{
if (!columnTable.ContainsKey(pair.Key))
columnTable[pair.Key] = new List<int>();
columnTable[pair.Key].AddRange(pair.Value.OrderBy(a => a));
}
}
var min = columnTable.Keys.Min();
var max = columnTable.Keys.Max();
for (int i = min; i <= max; i++)
results.Add(columnTable[i]);
return results;
}
}
}