Consider all the leaves of a binary tree, from left to right order, the values of those leaves form a leaf value sequence.
For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).
Two binary trees are considered leaf-similar if their leaf value sequence is the same.
Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.
Example 1:
Input: root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8] Output: true Example 2:
Input: root1 = [1], root2 = [1] Output: true Example 3:
Input: root1 = [1], root2 = [2] Output: false Example 4:
Input: root1 = [1,2], root2 = [2,2] Output: true Example 5:
Input: root1 = [1,2,3], root2 = [1,3,2] Output: false
/**
* 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 Solution {
List<int> leaf1 = new List<int>();
List<int> leaf2 = new List<int>();
public bool LeafSimilar(TreeNode root1, TreeNode root2) {
Helper(root1,true);
Helper(root2,false);
if(leaf1.Count()!=leaf2.Count()){
return false;
}
for(int i=0;i<leaf1.Count();i++){
if(leaf1[i]!=leaf2[i]){
return false;
}
}
return true;
}
private void Helper(TreeNode root, bool isLeftTree){
if(root==null){
return;
}
if(root.left==null && root.right == null){
if(isLeftTree){
leaf1.Add(root.val);
}
else{
leaf2.Add(root.val);
}
}
Helper(root.left,isLeftTree);
Helper(root.right,isLeftTree);
}
}Time Complexity: O(n)
Space Complexity: O(1)
