My O(n) Solution | Accepted | Java | Beats 100%
\nclass Solution {\n    int left = 0, right = 0;\n    public boolean btreeGameWinningMove(TreeNode root, int n, int x) {\n        \n        helper(root, x);\n  
```\nclass Solution {\n    int left = 0, right = 0;\n    public boolean btreeGameWinningMove(TreeNode root, int n, int x) {\n        \n        helper(root, x);\n        int o = n - left - right -1 ;\n        return left > n/2 || right > n/2 || o > n/2;\n        \n    }\n    \n    public int helper(TreeNode node, int x){\n        if(node == null) return 0;\n        \n        int l = helper(node.left, x);\n        int r = helper(node.right, x);\n        \n        if(node.val == x){\n            left = l;\n            right = r;\n        }\n        \n        return l + r + 1;\n    }\n}\n```
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