剑指offer32-III从上到下打印二叉树

此题和之前的剑指offer32-I、II.从上到下打印二叉树大致相同在BFS的基础上只是添加了一个重排序的过程。具体代码如下：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */


/**
 * Return an array of arrays of size *returnSize.
 * The sizes of the arrays are returned as *returnColumnSizes array.
 * Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
 */
 typedef struct queue
 {
     int front;
     int rear;
     struct TreeNode *data[1009];
 }QUEUE;
int** levelOrder(struct TreeNode* root, int* returnSize, int** returnColumnSizes){
    *returnSize=0;
    if(root==NULL)
    {
        return NULL;
    }
    QUEUE *q=(QUEUE *)malloc(sizeof(QUEUE)*1009);
     q->front=0;
     q->rear=1;
     q->data[0]=root;
    int **res=(int **)malloc(sizeof(int *)*1009);       //定义一个二维数组
    //bfs
    while(q->front!=q->rear)
    {
        int levelcount=q->rear-q->front;      //二叉树每层的个数也就是数组中每行有多少个数。
        res[*returnSize]=(int *)calloc(levelcount,sizeof(int)); //给数组中每一行分配levelcount个地址。
        (*returnColumnSizes)[*returnSize]=levelcount;
            for(int i=0;i<levelcount;i++)
            {
                if(q->data[(q->front)]->left)
                {
                    q->data[(q->rear)++]=q->data[q->front]->left;
                }
                if(q->data[(q->front)]->right)
                {
                    q->data[q->rear++]=q->data[q->front]->right;
                }
                if(*returnSize%2!=0)    //对奇数行号进行重排列
                {
                    res[*returnSize][levelcount-i-1]=q->data[q->front]->val;
                }
                else
                {
                     res[*returnSize][i]=q->data[q->front]->val;
                }
                q->front++;
            }
        (*returnSize)++;         //记录层数，即二维数组的行数。
    }
    return res;
}