leetcode297

  1 public class Codec
  2     {
  3         // Encodes a tree to a single string.
  4         public string serialize(TreeNode root)
  5         {
  6             if (root == null)
  7                 return "";
  8 
  9             Queue<TreeNode> queue = new Queue<TreeNode>();
 10             StringBuilder result = new StringBuilder();
 11 
 12             queue.Enqueue(root);
 13             while (true)
 14             {
 15                 if (queue.Count() == 0)
 16                     break;
 17 
 18                 int nodesAtLevel = queue.Count();
 19                 StringBuilder list = new StringBuilder();
 20                 for (int i = 0; i < nodesAtLevel; i++)
 21                 {
 22                     var node = queue.Dequeue();
 23                     if (node != null)
 24                     {
 25                         list.Append(node.val.ToString() + ",");
 26                         if (node.left != null)
 27                             queue.Enqueue(node.left);
 28                         else
 29                             queue.Enqueue(null);
 30 
 31                         if (node.right != null)
 32                             queue.Enqueue(node.right);
 33                         else
 34                             queue.Enqueue(null);
 35                     }
 36                     else
 37                     {
 38                         list.Append("null" + ",");
 39                     }
 40 
 41                 }
 42                 result.Append(list.ToString());
 43             }
 44             result.Remove(result.Length - 1, 1);
 45             return result.ToString();
 46         }
 47 
 48         // Decodes your encoded data to tree.
 49         public TreeNode deserialize(string data)
 50         {
 51             if (data.Length == 0)
 52                 return null;
 53             Queue<TreeNode> queue = new Queue<TreeNode>();
 54             var tlist = data.Split(',');
 55             var count = tlist.Length;
 56 
 57             foreach (var l in tlist)
 58             {
 59                 if (l != "null")
 60                 {
 61                     var t = new TreeNode(int.Parse(l));
 62                     queue.Enqueue(t);
 63                 }
 64                 else
 65                 {
 66                     queue.Enqueue(null);
 67                 }
 68             }
 69             var root = queue.Dequeue();
 70             var list = new List<TreeNode>();
 71             list.Add(root);
 72             while (queue.Any())
 73             {
 74                 var temp = new List<TreeNode>();
 75                 for (int i = 0; i < list.Count; i++)
 76                 {
 77                     var p = list[i];
 78                     var left = queue.Dequeue();
 79                     if (left != null)
 80                     {
 81                         p.left = left;
 82                     }
 83                     var right = queue.Dequeue();
 84                     if (right != null)
 85                     {
 86                         p.right = right;
 87                     }
 88                     if (p.left != null)
 89                     {
 90                         temp.Add(p.left);
 91                     }
 92                     if (p.right != null)
 93                     {
 94                         temp.Add(p.right);
 95                     }
 96                 }
 97                 list = temp;
 98             }
 99             return root;
100         }
101     }
posted on 2019-03-06 13:35 Sempron2800+ 阅读(330) 评论(0) 编辑收藏举报