LCA（最近公共祖先）问题

236. 二叉树的最近公共祖先 

public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { // LCA 问题 if (root == null) { return root; } if (root == p || root == q) { return root; } TreeNode left = lowestCommonAncestor(root.left, p, q); TreeNode right = lowestCommonAncestor(root.right, p, q); if (left != null && right != null) { return root; } else if (left != null) { return left; } else if (right != null) { return right; } return null; }