算法导论 红黑树 实现

Posted 2020-08-30

首先实现插入 左旋转 右旋转 并测试
暂时未考虑颜色转换

// rbTreeTest.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <memory>
#include <iostream>

using namespace std;

enum Color {
    red = 1,
    black
};

struct node {
    Color color_;
    std::shared_ptr<node> left_;
    std::shared_ptr<node> right_;
    std::shared_ptr<node> parent_;
    int value_;
    node() {
        left_ = right_ = parent_ = nullptr;
        value_ = -1;
        color_ = black;
    }
};

std::shared_ptr<node> nil(new node);


std::shared_ptr<node> CreateNode(Color color, int i) {
    std::shared_ptr<node> p(new node);
    p->color_ = color;
    p->left_ = nil;
    p->right_ = nil;
    p->parent_ = nil;
    p->value_ = i;
    return p;
}

void RightRotate(std::shared_ptr<node>& root, std::shared_ptr<node>& x) {
    std::shared_ptr<node> y = x->left_;
    x->left_ = y->right_;
    if (y->right_ != nil)
        y->right_->parent_ = x;
    y->parent_ = x->parent_;
    if (x->parent_ == nil){
        root = y;
    }
    else if (x->parent_->left_ == x) {
        x->parent_->left_ = y;
    }
    else {
        x->parent_->right_ = y;
    }

    y->right_ = x;
    x->parent_ = y;
}

void LeftRotate(std::shared_ptr<node>& root, std::shared_ptr<node>& x) {
    std::shared_ptr<node> y = x->right_;
    x->right_ = y->left_;
    if (y->left_ != nil)
        y->left_->parent_ = x;

    y->parent_ = x->parent_;
    if (x->parent_ == nil) {
        root = y;
    }
    else if (x->parent_->left_ == x) {
        x->parent_->left_ = y;
    }
    else {
        x->parent_->right_ = y;
    }
    y->left_ = x;
    x->parent_ = y;
}

void PrinTree(std::shared_ptr<node> root) {
    if (root == nil) {
        return;
    }
    std::cout << root->value_ << " ";
    if(root->left_!=nil)
        PrinTree(root->left_);
    if(root->right_ != nil)
        PrinTree(root->right_);
}

void test11() {
    std::shared_ptr<node> root = CreateNode(black, 2);
    root->parent_ = nil;
    std::shared_ptr<node> x = root;
    std::shared_ptr<node> y = CreateNode(red, 1);
    root->left_ = y;
    y->parent_ = x;

    PrinTree(root);
    std::cout << std::endl;
    RightRotate(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

void test1() {
    //构建测试1，2
    std::shared_ptr<node> root = CreateNode(black, 1);
    root->parent_ = nil;
    std::shared_ptr<node> x = root;
    root->right_ = CreateNode(red, 2);
    root->right_->parent_ = root;

    
    PrinTree(root);
    std::cout << std::endl;
    LeftRotate(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

void test22() {
    std::shared_ptr<node> root = CreateNode(black, 4);
    root->parent_ = nil;
    std::shared_ptr<node> x = root;

    std::shared_ptr<node> y = CreateNode(black, 3);
    x->left_ = y;
    y->parent_ = x;

    std::shared_ptr<node> z = CreateNode(black, 2);
    y->left_ = z;
    z->parent_ = y;

    PrinTree(root);
    std::cout << std::endl;

    RightRotate(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}


void test2() {
    std::shared_ptr<node> root = CreateNode(black, 1);
    root->parent_ = nil;
    root->right_ = CreateNode(red, 2);
    root->right_->parent_ = root;

    std::shared_ptr<node> x = root->right_;

    std::shared_ptr<node> y = CreateNode(red, 3);
    x->right_ = y;
    y->parent_ = x;
    PrinTree(root);
    std::cout << std::endl;

    LeftRotate(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

void test33() {
    std::shared_ptr<node> root = CreateNode(black, 9);
    root->parent_ = nil;
    std::shared_ptr<node> a = root;

    std::shared_ptr<node> b = CreateNode(black, 10);
    a->right_ = b;
    b->parent_ = a;

    std::shared_ptr<node> c = CreateNode(black, 6);
    a->left_ = c;
    c->parent_ = a;

    std::shared_ptr<node> d = CreateNode(black, 8);
    c->right_ = d;
    d->parent_ = c;

    std::shared_ptr<node> e = CreateNode(black, 4);
    c->left_ = e;
    e->parent_ = c;

    std::shared_ptr<node> f = CreateNode(black, 2);
    e->left_ = f;
    f->parent_ = e;

    std::shared_ptr<node> g = CreateNode(black, 5);
    e->right_ = g;
    g->parent_ = e;

    PrinTree(root);
    std::cout << std::endl;

    RightRotate(root, c);

    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

void test3() {
    std::shared_ptr<node> root = CreateNode(black, 1);
    root->parent_ = nil;

    root->right_ = CreateNode(red, 3);
    root->right_->parent_ = root;

    std::shared_ptr<node> x = root->right_;

    std::shared_ptr<node> y = CreateNode(red, 2);
    x->left_ = y;
    y->parent_ = x;

    std::shared_ptr<node> z = CreateNode(red, 4);
    x->right_ = z;
    z->parent_ = x;

    PrinTree(root);
    std::cout << std::endl;

    LeftRotate(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}


void test4() {
    std::shared_ptr<node> root = CreateNode(black, 5);
    root->parent_ = nil;

    std::shared_ptr<node> a = CreateNode(red, 2);
    root->left_ = a;
    a->parent_ = root;

    std::shared_ptr<node> b = CreateNode(red, 7);
    root->right_ = b;
    b->parent_ = root;

    std::shared_ptr<node> c = CreateNode(red, 6);
    b->left_ = c;
    c->parent_ = b;

    std::shared_ptr<node> d = CreateNode(red, 9);
    b->right_ = d;
    d->parent_ = b;

    std::shared_ptr<node> e = CreateNode(red, 8);
    d->left_ = e;
    e->parent_ = d;

    std::shared_ptr<node> f = CreateNode(red, 10);
    d->right_ = f;
    f->parent_ = d;

    PrinTree(root);
    std::cout << std::endl;

    LeftRotate(root, b);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

void RBInsert(std::shared_ptr<node>& root, std::shared_ptr<node>& ins) {
    std::shared_ptr<node> y = nil;
    std::shared_ptr<node> x = root;

    while (x != nil) {
        y = x;
        if (ins->value_ < x->value_) {
            x = x->left_;
        }
        else {
            x = x->right_;
        }
    }
    ins->parent_ = y;
    if (y == nil) {
        root = ins;
    }
    else if (ins->value_ < y->value_) {
        y->left_ = ins;
    }
    else {
        y->right_ = ins;
    }
    ins->left_ =ins->right_ = nil;
    ins->color_ = red;
    // todo  fixup
}

void TestInsert() {
    std::shared_ptr<node> root = nil;
    std::shared_ptr<node> x = CreateNode(red, 7);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red,4);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 11);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 3);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 6);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 9);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 18);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 2);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 14);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 19);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 12);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 17);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 22);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    x = CreateNode(red, 20);
    RBInsert(root, x);
    PrinTree(root);
    std::cout << std::endl;

    std::cout << std::endl;
}

int main()
{
    TestInsert();
    test1();
    test2();
    test3();
    test4();
    test11();
    test22();
    test33();

    return 0;
}

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