LeetCode：236、二叉树的最近公共祖先

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        return traversal(root,p,q);
    }
    public TreeNode traversal(TreeNode root, TreeNode p, TreeNode q) {
        if(root==null)return null;
        if(root==q||root==p)return root;
        TreeNode left=traversal(root.left,p,q);
        TreeNode right=traversal(root.right,p,q);
        if(left!=null&&right!=null)return root;
        if(left==null&&right!=null)return right;
        else if(left!=null&&right==null)return left;
        else return null;
    }
}

236. 二叉树的最近公共祖先 - 力扣（LeetCode）