Leetcode 872. Leaf-Similar Trees

872. Leaf-Similar Trees

難易度

Easy

アプローチ

DFS

/**
 * 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 ArrayList<Integer> arrayList1;
    public ArrayList<Integer> arrayList2;

    
    public boolean leafSimilar(TreeNode root1, TreeNode root2) {
        arrayList1 = new ArrayList<>();
        arrayList2 = new ArrayList<>();
        dfs1(root1);
        dfs2(root2);

        if (arrayList1.size() != arrayList2.size()) {
            return false;
        }

        for (int i = 0; i < arrayList1.size(); i++) {
            if (arrayList1.get(i).intValue() != arrayList2.get(i).intValue()) {
                return false;
            }
        }

        return true;
    }
    
    public  void dfs1(TreeNode root){
        if(root == null){
            return;
        }

        dfs1(root.left);
        dfs1(root.right);

        if(root.left == null && root.right == null){
            arrayList1.add(root.val);
        }
    }
    
    public  void dfs2(TreeNode root){
        if(root == null){
            return;
        }

        dfs2(root.left);
        dfs2(root.right);

        if(root.left == null && root.right == null){
            arrayList2.add(root.val);
        }
    }
}