leetcode100

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    List<TreeNode> list1 = new List<TreeNode>();
        List<TreeNode> list2 = new List<TreeNode>();

        void postTree(TreeNode tree, int type)
        {
            if (type == 1)
            {
                list1.Add(tree);
            }
            else
            {
                list2.Add(tree);
            }
            if (tree != null)
            {
                if (tree.left != null)
                {
                    postTree(tree.left, type);
                }
                else
                {
                    postTree(null, type);
                }

                if (tree.right != null)
                {
                    postTree(tree.right, type);
                }
                else
                {
                    postTree(null, type);
                }
            }

        }

        public bool IsSameTree(TreeNode p, TreeNode q)
        {
            postTree(p, 1);
            postTree(q, 2);

            var len1 = list1.Count;
            var len2 = list2.Count;

            if (len1 != len2)
            {
                return false;
            }
            else
            {
                for (int i = 0; i < len1; i++)
                {
                    if (list1[i] == null && list2[i] != null)
                    {
                        return false;
                    }
                    if (list1[i] != null && list2[i] == null)
                    {
                        return false;
                    }
                    if (list1[i] != null && list2[i] != null && list1[i].val != list2[i].val)
                    {
                        return false;
                    }
                }
                return true;
            }
        }
}

https://leetcode.com/problems/same-tree/#/description