Populating Next Right Pointers in Each Node

 1     //按说层次遍历最方便了，但是空间复杂度不满足题意
 2     //遍历吧，可是像例子中的，5—>6怎么实现呢
 3     //You may assume that it is a perfect binary tree (ie, all leaves are at the same level, and every parent has two children).
 4     //这个提示是什么意思？
 5     void connect(TreeLinkNode *root) {
 6         if(root==NULL)
 7             return;
 8         if(root->left)
 9             root->left->next=root->right;
10         if(root->next&&root->right)
11             root->right->next=root->next->left;
12         connect(root->left);
13         connect(root->right);
14         //Initially, all next pointers are set to NULL.因为这句话，所以根节点的next和最右结点的next就不用指定为NULL啦
15     }