*BST（二叉搜索樹）

今天是2017/5/22，DCDCBigBig的第十篇博文

BST

//這tm是什麼鬼啊。。。好像是N年前的東西了吧。。。
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<cmath>
#define nil NULL
using namespace std;
struct point{
    int data;
    point *lc;
    point *rc;
    int num;
};
point *root;
void ins(point* &t,int x){
    if(t==nil){
        t=(point *)malloc(sizeof(point));
        t->data=x;
        t->lc=nil;
        t->rc=nil;
        t->num=1;
    }else{
        if(x<t->data){ins(t->lc,x);}
        if(x>t->data){ins(t->rc,x);}
        if(x==t->data){t->num++;}
    }
}
void write(point *t){
    if(t==nil){return;}
    write(t->lc);
    for(int i=1;i<=t->num;i++){
        printf("%d ",t->data);
    }
    write(t->rc);
}
void wwrite(point *t){
    if(t==nil){return;}
    printf("(");
    wwrite(t->lc);
    printf("%d",t->data);
    wwrite(t->rc);
    printf(")");
}
point *fi(point *t,int x){
    if(t==nil){return nil;}
    if(t->data==x){return t;}
    if(t->data>x){return fi(t->lc,x);}
    if(t->data<x){return fi(t->rc,x);}
}
int find_min(point *t){
    if(t->lc==nil){return t->data;}
    return find_min(t->lc);
}
int find_max(point *t){
    if(t->rc==nil){return t->data;}
    return find_max(t->rc);
}
int main(){
    char n;
    int m;
    while(true){
        cin>>n;
        if(n=='I'){
            scanf("%d\n",&m);
            ins(root,m);
        }else if(n=='W'){
            write(root);
            printf("\n");
        }else if(n=='P'){
            wwrite(root);
            printf("\n");
        }else if(n=='E'){
            break;
        }else if(n=='B'){
            if(root!=nil){
                printf("%d\n",find_max(root));
            }else{cout<<endl;}
        }else if(n=='S'){
            if(root!=nil){
                printf("%d\n",find_min(root));
            }else{cout<<endl;}
        }else if(n=='C'){
            root=nil;
        }else{
            printf("It isn't a right letter!\n");
        }
    }
    return 0;
}

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