My-LeetCode-solutions/lc-235.java at master · nerozenJL/My-LeetCode-solutions · GitHub

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/**
 * 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) {
        if(root == null) return null;
        else {
            if(p.val < root.val && q.val < root.val) {
                return lowestCommonAncestor(root.left, p, q);
            }
            if(p.val > root.val && q.val > root.val) {
                return lowestCommonAncestor(root.right, p, q);
            }
            if(p.val <= root.val && q.val >= root.val) {
                return root;
            }
            if(q.val >= root.val && q.val <= root.val) {
                return root;
            }else {
                return root;
            }
        }
    }
}