[LeetCode/Easy] 965. Univalued Binary Tree

1. Input

1) TreeNode root

 

2. Output

1) root의 모든 노드의 값이 같으면 true, 다르면 false를 반환

 

3. Constraint

1) 노드 수의 범위는 [1, 100]이다.

2) 0 <= Node.val < 100

 

4. Example

Input: root = [1,1,1,1,1,null,1] -> Output: true

Input: root = [2,2,2,5,2] -> Output: false

 

5. Code

1) 첫 코드(2023/06/06)

/**
 * 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 isUnivalTree(TreeNode root) {
        boolean ans = true;
        Queue<TreeNode> q = new LinkedList<>();
        q.add(root);
        int v = root.val;
        while(!q.isEmpty()){
            TreeNode c = q.remove();
            if(c.val!=v) { ans = false; break; }
            if(c.left!=null) q.add(c.left);
            if(c.right!=null) q.add(c.right);
        }
        return ans;
    }
}

- 100%, 95%