1. 利用队列进行层次遍历
2. 获取各层的节点的个数

循环队列可以参考这篇文章

代码如下：

// 获取二叉树每一层的结点的个数
int *NumberOfFloorTree(BiTree *biTree, int *number, int deep) {// floor 二叉树的层数// deep 二叉树的深度if (!biTree) return false;QueueTree Q;int i = 2;BiTree *middle = biTree;BiTree middle_null;middle_null.leftChild = NULL;middle_null.rightChild = NULL;middle_null.data = ' ';Q = InitQueueTree(20);ENQueueTree(&Q, middle);// 将空结点入列，作为每一层结束的标志ENQueueTree(&Q, &middle_null);number[1] = 1;while (Q.tag != 0 && i <= deep) {DEQueueTree(&Q, &middle);if (middle->data == ' ') {ENQueueTree(&Q, &middle_null);i++;continue;}if (middle->leftChild) {number[i]++;ENQueueTree(&Q, middle->leftChild);}if (middle->rightChild) {number[i]++;ENQueueTree(&Q, middle->rightChild);}}
}