leetcode 117. Populating Next Right Pointers in Each Node II 最简单栈解法

做完上一题发现这一题只是把完美二叉树改成了普通二叉树。

思路和解法完全不变，连代码都一样。

// 代码与Problem116一模一样 // Runtime: 0 ms, faster than 100.00% of Java online submissions for Populating Next Right Pointers in Each Node II. //Memory Usage: 38.5 MB, less than 7.13% of Java online submissions for Populating Next Right Pointers in Each Node II. private final Stack<Node> stack = new Stack<>(); public Node connect(Node root) { if (root == null) return null; root.next = stack.isEmpty() ? null : stack.pop(); connect(root.right); connect(root.left); stack.push(root); return root; }