count-dominant-nodes-in-a-binary-tree

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Algorithms

You are given the <code>root</code> of a complete binary tree.

A node <code>x</code> is called dominant if its value is equal to the maximum value among all nodes in the subtree rooted at <code>x</code>.

Return the number of dominant nodes in the tree.

&nbsp;
Example 1:

<div class="example-block">
<img alt="" src="https://assets.leetcode.com/uploads/2026/06/13/tnew.png" style="width: 300px; height: 193px;" />

Input: root = [5,3,8,2,4,7,1]

Output: 5

Explanation:

<ul>
	<li>The leaf nodes with values 2, 4, 7, and 1 are dominant.</li>
	<li>The node with value 8 is dominant because its value is the maximum value in its subtree <code>[8, 7, 1]</code>.</li>
	<li>Thus, the answer is 5.</li>
</ul>
</div>

Example 2:

<div class="example-block">
<img alt="" src="https://assets.leetcode.com/uploads/2026/06/15/t9.png" style="width: 250px; height: 183px;" />

Input: root = [1,2,3,1,2]

Output: 4

Explanation:

<ul>
	<li>The leaf nodes with values 1, 2, and 3 are dominant.</li>
	<li>The node with value 2 whose subtree is <code>[2, 1, 2]</code> is dominant because its value is the maximum value in its subtree.</li>
	<li>Thus, the answer is 4.</li>
</ul>
</div>

&nbsp;
Constraints:

<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 105]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 109</code></li>
	<li>The tree is guaranteed to be a complete binary tree.</li>
</ul>

Weekly Contest 511

weekly-contest-511

countDominantNodes

Senior

Count Dominant Nodes in a Binary Tree

Tree

Depth-First Search

Binary Tree

Accepted

Wrong Answer

Memory Limit Exceeded

Output Limit Exceeded

Time Limit Exceeded

Runtime Error

Internal Error

Compile Error

Timeout

Restrictions Failed

cangjie

react

vanillajs

You are given the root of a complete binary tree.

A node x is called dominant if its value is equal to the maximum value among all nodes in the subtree rooted at x.

Return the number of dominant nodes in the tree.

 

Example 1:

[https://assets.leetcode.com/uploads/2026/06/13/tnew.png]

Input: root = [5,3,8,2,4,7,1]

Output: 5

Explanation:

 * The leaf nodes with values 2, 4, 7, and 1 are dominant.
 * The node with value 8 is dominant because its value is the maximum value in its subtree [8, 7, 1].
 * Thus, the answer is 5.

Example 2:

[https://assets.leetcode.com/uploads/2026/06/15/t9.png]

Input: root = [1,2,3,1,2]

Output: 4

Explanation:

 * The leaf nodes with values 1, 2, and 3 are dominant.
 * The node with value 2 whose subtree is [2, 1, 2] is dominant because its value is the maximum value in its subtree.
 * Thus, the answer is 4.

 

Constraints:

 * The number of nodes in the tree is in the range [1, 105].
 * 1 <= Node.val <= 109
 * The tree is guaranteed to be a complete binary tree.