广度优先搜索 - 深度优先搜索

#include<stack>
#include<iostream>

using namespace std;

//定义二叉树的节点
struct Node{
    int val;
    Node* left;
    Node* right;
    Node(int val_):val(val_),left(nullptr),right(nullptr){}
};

//广度优先搜索没有递归
stack<Node*> stk;
void bfs(Node* root)
{
    if (!root) return;
    stk.push(root);
    while (!stk.empty())
    {
        Node* cur = stk.top();
        cout <<"the val is: "<< cur->val <<endl;
        stk.pop();
        if (cur->left)  stk.push(cur->left);
        if (cur->right) stk.push(cur->left);
    }
}

//深度优先搜索用的是递归来实现
void dfs(Node* root)
{
    if (!root) return;
    cout <<"the val is: "<< root->val <<endl;
    dfs(root->left);
    dfs(root->right);
}