特定深度节点链表

题目链接：力扣（LeetCode）官网 - 全球极客挚爱的技术成长平台

经典BFS与简单链表结合的题目。

#define MAX_DEPTH (1000)struct ListNode** listOfDepth(struct TreeNode* tree, int* returnSize)
{*returnSize = 0;struct ListNode **ans = (struct ListNode **)malloc(sizeof(struct ListNode*) * MAX_DEPTH);struct TreeNode *quene[MAX_DEPTH];struct ListNode *pre = NULL;int front = 0;int rear = 0;if (tree) {quene[rear++] = tree;}while (front != rear) {int cnt = rear - front;for (int i = 0; i < cnt; i++) {if (i == 0) {ans[(*returnSize)] = (struct ListNode*)malloc(sizeof(struct ListNode)); // 每层的链表头pre = ans[(*returnSize)++];pre->val = quene[front]->val;pre->next = NULL;} else {struct ListNode *node = (struct ListNode*)malloc(sizeof(struct ListNode));node->val = quene[front]->val;node->next = NULL;pre->next = node;pre = pre->next;}if (quene[front]->left) {quene[rear++] = quene[front]->left;}if (quene[front]->right) {quene[rear++] = quene[front]->right;}front++;}}return ans;
}