LeetCode ：前序遍历二叉树(迭代）
本帖最后由 慵懒的勤快孩儿 于 2020-7-5 21:56 编辑若二叉树为空，则空操作返回，否则先访问根结点，然后前序遍历左子树，再前序遍历右子树。(为了方便理解，大佬的图让我搬过来了，嘿嘿嘿）
C语言实现：
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* struct TreeNode *left;
* struct TreeNode *right;
* };
*/
/**
* Note: The returned array must be malloced, assume caller calls free().
*/
int* preorderTraversal(struct TreeNode* root, int* returnSize){
struct TreeNode *stack;//数组代替栈
int top = -1;//栈空
int *result = (int*)malloc(sizeof(int) * 100);
int i = 0;
stack[++top] = root;
while(top != -1){
root = stack;
while(root){
result = root->val;
stack[++top] = root->right;
root = root->left;
}
}
*returnSize = i;
//printf("%d",*returnSize);
return result;
}
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