c++非递归深度优先遍历代码

下面是C++实现非递归深度优先遍历的代码：

#include <iostream>
#include <stack>
#include <vector>

using namespace std;

// 定义节点结构体
struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};

vector<int> dfs(TreeNode* root) {
    vector<int> res;
    if (!root) {
        return res;
    }

    stack<TreeNode*> s;
    s.push(root);

    while (!s.empty()) {
        TreeNode* cur = s.top();
        s.pop();
        res.push_back(cur->val);

        if (cur->right) {
            s.push(cur->right);
        }

        if (cur->left) {
            s.push(cur->left);
        }
    }

    return res;
}

int main() {
    TreeNode* root = new TreeNode(1);
    root->left = new TreeNode(2);
    root->right = new TreeNode(3);
    root->left->left = new TreeNode(4);
    root->left->right = new TreeNode(5);
    root->right->left = new TreeNode(6);
    root->right->right = new TreeNode(7);

    vector<int> res = dfs(root);
    for (auto val : res) {
        cout << val << " ";
    }

    return 0;
}

这里我们使用了一个栈来保存节点，从而实现了非递归的深度优先遍历。具体的实现细节可以参考代码中的注释。