【数据结构】二叉树DFS（深度优先搜索）_c++ 深度优先搜索(dfs)二叉树

静态实现（数组）

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+5;
struct Node{
    char value;
    int lson, rson;
}tree[N];
int index=1;
int newNode(char val)
{
    tree[index].value=val;
    tree[index].lson=tree[index].rson=0;
    return index++;
}
void insert(int &father,int child,int l_r){
    if(l_r==0)
        tree[father].lson=child;
    else
        tree[father].rson=child;

}

int dfn[N]={0};
int dfn_timer=0;

void dfn_order(int father)
{
    if(father!=0){
        dfn[father]=++dfn_timer;
        printf("dfn[%c]=%d;",tree[father].value,dfn[father]);
        dfn_order(tree[father].lson);
        dfn_order(tree[father].rson);
    }
}

int visit_timer=0;
void visit_order(int father)
{
    if(father!=0){
        printf("visit[%c]=%d;",tree[father].value,++visit_timer);
        visit_order(tree[father].lson);
        visit_order(tree[father].rson);
        printf("visit[%c]=%d;",tree[father].value,++visit_timer);
    }
}

int deep[N]={0};
int deep_timer=0;
void deep_node(int father)
{
    if(father!=0)
    {
        deep[father]=++deep_timer;
        printf("deep[%c]=%d;",tree[father].value,deep[father]);
        deep_node(tree[father].lson);
        deep_node(tree[father].rson);
        deep_timer--;
    }
}

int num[N]={0};
int num_node(int father){
    if(father==0)
        return 0;
    else
    {
        num[father]=num_node(tree[father].lson)+num_node(tree[father].rson)+1;
        printf("num[%c]=%d;",tree[father].value,num[father]);
        return num[father];
    }
}

void preorder(int father)
{
    if(father!=0) {
        cout << tree[father].value << " ";
        preorder(tree[father].lson);
        preorder(tree[father].rson);
    }
}

void inorder(int father)
{
    if(father!=0) {
        inorder(tree[father].lson);
        cout << tree[father].value << " ";
        inorder(tree[father].rson);
    }
}

void postorder(int father)
{
    if(father!=0) {
        postorder(tree[father].lson);
        postorder(tree[father].rson);
        cout << tree[father].value << " ";
    }
}

int buildtree()
{
    int A=newNode('A');
    int B=newNode('B');
    int C=newNode('C');
    int D=newNode('D');
    int E=newNode('E');
    int F=newNode('F');
    int G=newNode('G');
    int H=newNode('H');
    int I=newNode('I');
    insert(E,B,0);
    insert(E,G,1);
    insert(B,A,0);
    insert(B,D,1);
    insert(G,F,0);
    insert(G,I,1);
    insert(D,C,0);
    insert(I,H,0);
    int root=E;
    return root;
}
int main()
{
    int root=buildtree();
    cout<<"dfn_order:";
    dfn_order(root);
    cout<<endl;
    cout<<"visit_order:";
    visit_order(root);
    cout<<endl;
    cout<<"deep_node:";
    deep_node(root);
    cout<<endl;
    cout<<"num_node:";
    num_node(root);
    cout<<endl;
    cout<<"preorder:";
    preorder(root);
    cout<<endl;
    cout<<"inorder:";
    inorder(root);
    cout<<endl;
    cout<<"postorder:";
    postorder(root);
    cout<<endl;
    return 0;
}
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动态实现（链表）

#include <bits/stdc++.h>
using namespace std;
struct node{
    char value;
    node* left;
    node* right;
    node(char value='#',node *left=NULL,node* right=NULL):value(value),left(left),right(right){}
};
void preorder(node *root){
    if(root!=NULL)
    {
        cout<<root->value<<" ";
        preorder(root->left);
        preorder(root->right);
    }
}
void inorder(node *root){
    if(root!=NULL)
    {
        preorder(root->left);
        cout<<root->value<<" ";
        preorder(root->right);
    }
}
void postorder(node *root){
    if(root!=NULL)
    {
        preorder(root->left);
        preorder(root->right);
        cout<<root->value<<" ";
    }
}
void remove_tree(node* root){
    if(root==NULL)
        return;
    remove_tree(root->left);
    remove_tree(root->right);
    delete root;
}
int main()
{
    node *A=new node('A');
    node *B=new node('B');
    node *C=new node('C');
    node *D=new node('D');
    node *E=new node('E');
    node *F=new node('F');
    node *G=new node('G');
    node *H=new node('H');
    node *I=new node('I');
    E->left=B;E->right=G;
    B->left=A;B->right=D;
    G->left=F;G->right=I;
    D->left=C;I->left=H;
    cout<<"Preorder: ";preorder(E);cout<<endl;
    cout<<"Inorder: ";inorder(E);cout<<endl;
    cout<<"Postorder: ";postorder(E);cout<<endl;
    remove_tree(E);
    return 0;
}
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