二叉搜索樹

#include "pch.h"
#include <iostream>
#include <algorithm>
#include <queue>

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 if (x > p->val) {
		return find(p->rch, x);
	}
}

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