二叉搜索樹_實現

《挑戰程序設計競賽》，初級篇–樹

// 二叉搜索樹_實現
#include <iostream>
#include <cstdio>
using namespace std;

struct node
{
    int val;
    node *lch,*rch;
};

node *insert(node *p, int x)
{
    if(p ==  NULL)
    {
        node *q = new node;
        q->val = x;
        q->lch = q->rch = NULL;
        return q;
    }
    else
    {
        if(x < p->val) p->lch = insert(p->lch, x);
        else p->rch = insert(p->rch, x);
        return p;
    }
}

bool find(node *p, int x)
{
    if(p == NULL) return false;
    else if(x == p->val) return true;
    else if(x < p->val) return find(p->lch, x);
    else return find(p->rch, x);
}

node *remove(node *p, int x)
{
    if(p == NULL) return NULL;
    else if(x < p->val) p->lch = remove(p->lch, x);
    else if(x > p->val) p->rch = remove(p->rch, x);
    else if(p->lch == NULL)
    {
        node *q = p->rch;
        delete p;
        return q;
    }
    else if(p->lch->rch = NULL)
    {
        node *q = p->lch;
        q->rch = p->rch;
        delete p;
        return q;
    }
    else{
        node *q;
        for(q = p->lch; q->rch->rch != NULL; q = q->rch);
        node *r = q->rch;
        q->rch = r->lch;
        r->lch = p->lch;
        r->rch = p->rch;
        delete p;
        return r;
    }
    return p;
}

int main()
{
    node *root = NULL;
    root = insert(root,1);
    cout<<find(root,1);
}