<p>Given the <code>root</code> of a binary tree with unique values and the values of two different nodes of the tree <code>x</code> and <code>y</code>, return <code>true</code> <em>if the nodes corresponding to the values </em><code>x</code><em> and </em><code>y</code><em> in the tree are <strong>cousins</strong>, or </em><code>false</code><em> otherwise.</em></p>

<p>Two nodes of a binary tree are <strong>cousins</strong> if they have the same depth with different parents.</p>

<p>Note that in a binary tree, the root node is at the depth <code>0</code>, and children of each depth <code>k</code> node are at the depth <code>k + 1</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2019/02/12/q1248-01.png" style="width: 304px; height: 270px;" />
<pre>
<strong>Input:</strong> root = [1,2,3,4], x = 4, y = 3
<strong>Output:</strong> false
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2019/02/12/q1248-02.png" style="width: 334px; height: 266px;" />
<pre>
<strong>Input:</strong> root = [1,2,3,null,4,null,5], x = 5, y = 4
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2019/02/13/q1248-03.png" style="width: 267px; height: 258px;" />
<pre>
<strong>Input:</strong> root = [1,2,3,null,4], x = 2, y = 3
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the tree is in the range <code>[2, 100]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 100</code></li>
	<li>Each node has a <strong>unique</strong> value.</li>
	<li><code>x != y</code></li>
	<li><code>x</code> and <code>y</code> are exist in the tree.</li>
</ul>

class Solution {
public:
    

    bool isCousins(TreeNode* root, int x, int y) {
        if (!root) return false;
        
        queue<TreeNode*> q;
        q.push(root);
        
        int level = 0;
        int parentX = -1, parentY = -1;
        int levelX = -1, levelY = -1;
        
        while (!q.empty()) {
            int size = q.size();
            level++;
            
            for (int i = 0; i < size; i++) {
                TreeNode* node = q.front();
                q.pop();
                
                if (node->left) {
                    q.push(node->left);
                    if (node->left->val == x) {
                        parentX = node->val;
                        levelX = level;
                    } else if (node->left->val == y) {
                        parentY = node->val;
                        levelY = level;
                    }
                }
                
                if (node->right) {
                    q.push(node->right);
                    if (node->right->val == x) {
                        parentX = node->val;
                        levelX = level;
                    } else if (node->right->val == y) {
                        parentY = node->val;
                        levelY = level;
                    }
                }
            }
        }
        
        if (parentX == -1 || parentY == -1) return false;
        return (levelX == levelY) && (parentX != parentY);
    }
};
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