Populating Next Right Pointers in Each Node

这个题目感觉不会做
抄的代码在这里再写一遍吧

struct TreeLinkNode {    int val;    struct TreeLinkNode *left, *right, *next;};void connect(struct TreeLinkNode *root) {    if(root==NULL) {        return ;    }    struct TreeLinkNode *pre=root;    struct TreeLinkNode *cur=NULL;    while(pre->left) {        cur=pre;        while(cur) {            cur->left->next=cur->right;            if(cur->next) {                cur->right->next=cur->next->left;            }            cur=cur->next;        }        pre=pre->left;    }}

好难