题解 | #二叉树的中序遍历#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param root TreeNode类 
 * @return int整型一维数组
 * @return int* returnSize 返回数组行数
 */
#include <stdlib.h>
static int num = 0;
void inorder(struct TreeNode* root, *a)
{
    if(root==NULL)
        return ;

    inorder(root->left,a);
    a[num++] = root->val;
    inorder(root->right,a);
}

int* inorderTraversal(struct TreeNode* root, int* returnSize ) {
    // 树上节点数满足0≤n≤1000
    int* a = (int*)malloc(sizeof(int)*1000);
    inorder(root, a);
    *returnSize = num;
    return a;
}