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  • 二叉搜索树的随机化插入和伸展插入操作(平摊法)

    源码例如以下:

    #include <stdlib.h>
    #include <stdio.h>
    //#define Key int
    #define hl h->l
    #define hr h->r
    #define hlr h->l->r
    #define hll h->l->l
    #define hrr h->r->r
    #define hrl h->r->l
    typedef int Key;
    struct Item{
    	Key key;
    	char c;
    };
    typedef struct STnode* link;
    struct STnode{
    	Item item ; link l,r; int N;
    };
    
    static link head , z ;
    static struct Item NULLitem ;
    
    Key key(Item item){
    	return item.key;
    }
    //创建一个节点 
    link NEW(Item item, link l,link r, int N){
    	link x = (link)malloc(sizeof *x);
    	x->item = item;x->l = l;x->r = r;x->N = N;
    	if(head==z)head=x; //这句话不能少!!

    。 return x; } //初始化 void STinit(){ head = ( z = NEW(NULLitem,0,0,0)); } //右旋转 顺时针旋转 link rotR(link h){ link x = h->l; h->l = x->r; x->r=h; } //左旋转 逆时针旋转 link rotL(link h){ link x = h->r; h->r = x->l; x->l=h; } //根插入程序 link insertT(link h, Item item){ // Key v = key(item), t = key(h->item); char v = item.c, t = h->item.c; if(h==z)return NEW(item,z,z,1); if(v<t) {h->l = insertT(h->l,item); h = rotR(h); } else {h->r = insertT(h->r,item); h = rotL(h);} (h->N)++;return h; } //随机化插入程序 link insertR(link h, Item item){ // Key v = key(item), t = key(h->item); char v = item.c, t = h->item.c; if(h==z)return NEW(item,z,z,1); if(rand() < RAND_MAX / (h->N+1)) return insertR(h,item); //使得新节点出如今树根的概率是1/(N+1) if(v<t) {h->l = insertR(h->l,item); h = rotR(h); } else {h->r = insertR(h->r,item); h = rotL(h);} (h->N)++;return h; } //伸展插入 link splay(link h, Item item) { char v = item.c, t = h->item.c; if(h==z)return NEW(item,z,z,1); if(v<t){ if(hl==z)return NEW(item,z,h,h->N+1); if(v<hl->item.c){ hll=splay(hll,item); h = rotR(h); }else{ hlr = splay(hlr,item); hl = rotL(hl); } return rotR(h); } else { if(hr==z)return NEW(item,h,z,h->N+1); if(v>hr->item.c){ hrr=splay(hrr,item); h = rotL(h); }else{ hrl = splay(hrl,item); hr = rotR(hr); } return rotL(h); } } //BST插入主程序 void STinsert(Item item){ //新插入的节点都会当作根节点 head = splay(head,item); } void sortR(link h){ if(h==z)return; printf("%c ",h->item.c); sortR(h->l); sortR(h->r); } //二叉搜索树排序 void STsort(link h){ sortR(h); } void test(){ struct Item item1 = {322,'a'}; struct Item item2 = {23,'s'}; struct Item item3 = {2,'e'}; struct Item item4 = {332,'r'}; struct Item item5 = {332,'c'}; struct Item item6 = {332,'h'}; struct Item item7 = {112,'i'}; STinit(); STinsert(item1);STinsert(item2); STinsert(item3);STinsert(item4); STinsert(item5);STinsert(item6); STinsert(item7); STsort(head); } main(){ test(); }



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  • 原文地址:https://www.cnblogs.com/mthoutai/p/6888342.html
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