标签：
Given a binary tree, return the vertical order traversal of its nodes‘ values. (ie, from top to bottom, column by column).
If two nodes are in the same row and column, the order should be from left to right.
Examples:
[3,9,20,null,null,15,7], 3
/ / 9 20
/ / 15 7
return its vertical order traversal as:
[ [9], [3,15], [20], [7] ]
[3,9,8,4,0,1,7], 3
/ / 9 8
/\ / / \/ 4 01 7
return its vertical order traversal as:
[ [4], [9], [3,0,1], [8], [7] ]
[3,9,8,4,0,1,7,null,null,null,2,5] (0‘s right child is 2 and 1‘s left child is 5), 3
/ / 9 8
/\ / / \/ 4 01 7
/ / 5 2
return its vertical order traversal as:
[ [4], [9,5], [3,0,1], [8,2], [7] ]
public IList<IList<int>> VerticalOrder(TreeNode root) { var res = new List<IList<int>>(); if(root == null) return res; var hashtable = new Dictionary<int,List<int>>(); Queue<TreeNode> queue = new Queue<TreeNode>(); Queue<int> queueDeep = new Queue<int>(); queue.Enqueue(root); queueDeep.Enqueue(0); while(queue.Count >0 ) { var a = queue.Dequeue(); int deep = queueDeep.Dequeue(); if(a.left != null) { queue.Enqueue(a.left); queueDeep.Enqueue(deep+1); } if(a.right != null) { queue.Enqueue(a.right); queueDeep.Enqueue(deep-1); } if(hashtable.ContainsKey(deep)) { var temp = (List<int>)hashtable[deep]; temp.Add(a.val); hashtable[deep] = temp; } else { hashtable.Add(deep,new List<int>{a.val}); } } var sortHashtable = hashtable.OrderByDescending(x=>x.Key).ToDictionary(x=> x.Key,x=>x.Value); foreach(var pair in sortHashtable) { res.Add(pair.Value); } return res; }
314. Binary Tree Vertical Order Traversal
标签：
原文地址：http://www.cnblogs.com/renyualbert/p/5889082.html
