Leetcode

872. Leaf-Similar Trees

by hooni posted May 04, 2020
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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.

 

Constraints:

  • Both of the given trees will have between 1 and 200 nodes.
  • Both of the given trees will have values between 0 and 200


/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public boolean leafSimilar(TreeNode root1, TreeNode root2) {
        List<TreeNode> list1 = new ArrayList<>();
        List<TreeNode> list2 = new ArrayList<>();
        
        findLeaves(root1, list1);
        findLeaves(root2, list2);
        
        if(list1.size() != list2.size()){
            return false;
        }
        
        int loop = list1.size();
        for(int i=0; i<loop; i++){
            TreeNode node1 = list1.get(i);
            TreeNode node2 = list2.get(i);
            //System.out.println(node1+" == "+node2);
            if(node1.val != node2.val){
                return false;
            }
        }
        
        return true;
    }
    
    public void findLeaves(TreeNode node, List<TreeNode> list){
        if(node == null){
            return;
        }
        
        findLeaves(node.left, list);
        findLeaves(node.right, list);
        
        if(node.left == null && node.right == null){
            list.add(node);
        }
    }
}

[문제] https://leetcode.com/problems/leaf-similar-trees/