标签:Lowest Binary right return Tree TreeNode null root left
When we get this problem, we need to confirm the following 2 questions:
1. Can root, p or q be null? (No)
2. Can p be equal to q? (No)
We look "root" as a pointer, the point will check recursively of it's left and right sub-tree.
If the left return null, the p and q must be in right sub-tree, and if the right return null, the p and q must be in left sub-tree.
But if both left and right are not null, the p and q must be one in left and one in right, the current point should be the result.
public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { if(root ==null) return null; if(root==p || root==q) return root; TreeNode left = lowestCommonAncestor(root.left, p, q); TreeNode right = lowestCommonAncestor(root.right, p, q); if(left==null) return right; else if(right==null) return left; else return root; }
标签:Lowest,Binary,right,return,Tree,TreeNode,null,root,left 来源: https://www.cnblogs.com/feiflytech/p/15869972.html
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