Title: the nearest common ancestor of binary tree

Power button

// Explain 1
public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
         // LCA  problem 
        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;
        
         
    }
// Explain 2
 When binary tree   The left node of the current node   It must be smaller than the current node    The right node must be larger than the current node    Or vice versa , You can use the following algorithm 
if(root.val==p.val||root.val==q.val){
            return root;
        }
        if (root.val > p.val &&root.val > q.val) {
            return lowestCommonAncestor( root.right,  p,  q);
        }
        if (root.val < p.val &&root.val < q.val) {
            return lowestCommonAncestor( root.left,  p,  q);
        }
        return root;