C++实现一个简单的红黑树（RB_TREE）

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红黑树遵守的规则：一头（根）一脚（叶子节点）黑（黑色），黑同（从任意节点开始至NULL结点的黑色节点的个数相等）红不连（红色节点不能相连）
这里写图片描述
以下是红黑树的插入和旋转函数的简易实现：
#include <iostream>#include <assert.h>#include <string.h>using namespace std;typedef int Type;typedef enum{RED=0, BLACK}Color;    //节点的颜色typedef struct Node{    Color color;   //节点颜色    Type key;      //节点的值    struct Node *left, *right, *parent;  //左，右及父节点指针}*PNode;   //节点指针//树的结构定义typedef struct RB_TREE{    Node *root;   //根结点    Node *Nil;    //一个实现技巧，用于判断节点是否为空等}RB_TREE;Node *Buynode(){    Node *p = new Node;    assert(p != NULL);    memset(p, 0, sizeof(Node));    return p;}//构造一个空树void InitTree(RB_TREE &t){    t.Nil = Buynode();    t.root = t.Nil;    t.Nil->color = BLACK;    t.Nil->key = -1;}//左旋void RotateLeft(RB_TREE &t, Node *p){    Node *s = p->right;  //s为不平衡节点p的右树    p->right = s->left;   //将s的左树挂接至p的右树    if(s->left != t.Nil){  //若s的左树不为空,就改变其左树的父节点        s->left->parent = p;    }    s->parent = p->parent;  //改变s的父节点    if(p->parent == t.Nil){  //说明为p为根结点，旋转之后s为根结点        t.root = s;    }else if(p = p->parent->left){  //p之前位于左树就将s作为新的左树        p->parent->left = s;    }else{        p->parent->right = s;   //否则s为p的父节点的右树    }    s->left = p;   //p作s的左树    p->parent = s;  //更改p的父节点}//右旋void RotateRight(RB_TREE &t, Node *p){    Node *s = p->left;    p->left = s->right;    if(s->right != t.Nil){        s->right->parent = p;    }    s->parent = p->parent;    if(p->parent == t.Nil){        t.root = s;    }else if(p = p->parent->left){        p->parent->left = s;    }else{        p->parent->right = s;    }    s->right = p;    p->parent = s;}//调整树的平衡void Insert_Fixup(RB_TREE &t, Node *z){    Node *y;    while(z->parent->color == RED){   //红红相连不平衡        if(z->parent == z->parent->parent->left){   //左侧插入            y = z->parent->parent->right;   //y为插入节点的伯父节点            if(y->color == RED){                z->parent->color = BLACK;                z->parent->parent->color = RED;                y->color = BLACK;                z = z->parent->parent;                continue;            }else if(z == z->parent->right){  //左侧的内侧插入                z = z->parent;                RotateLeft(t, z);    //左旋            }            z->parent->color = BLACK;            z->parent->parent->color = RED;            RotateRight(t, z->parent->parent);   //右旋        }else{   //右侧插入            y = z->parent->parent->left;            if(y->color == RED){                z->parent->color = BLACK;                z->parent->parent->color = RED;                y->color = BLACK;                z = z->parent->parent;                continue;            }else if(z == z->parent->left){   //右侧的内侧插入                z = z->parent;                RotateRight(t, z);            }            z->parent->color = BLACK;            z->parent->parent->color = RED;            RotateLeft(t, z->parent->parent);        }    }    t.root->color = BLACK;}bool Insert(RB_TREE &t, Type x){    Node *p = t.Nil;    Node *s = t.root;    //找到合适的插入位置    while(s != t.Nil){        p = s;        if(x == s->key){            return false;        }else if(x < s->key){            s = s->left;        }else{            s = s->right;        }    }    //构造节点    Node *q = Buynode();    q->key = x;    q->parent = p;    //将节点插入树中的合适位置    if(p == t.Nil){   //则说明该树之前没有节点，则此节点为其根结点        t.root = q;    }else if(x < p->key){  //插入节点在节点p的左子树        p->left = q;    }else{    //插入节点在右子树        p->right = q;    }    //设置插入节点的信息    q->left = q->right = t.Nil;    q->color = RED;    //调整树的平衡    Insert_Fixup(t, q);    return true;}int main(){    int ar[] = {100, 40, 6};    RB_TREE rb;    InitTree(rb);    int n = sizeof(ar) / sizeof(int);    for(int i = 0; i < n; ++i){        Insert(rb, ar[i]);    }    return 0;}
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