Tyvj 1728 普通平衡树

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裸的平衡树，Splay和Treap均可水过，我的splay也是debug了好久….

#include<cstdio>#define MAXN 300005struct node {    int v, cnt, sz, ch[2], f;}t[MAXN];int rt, sz, n;#define Upd(r) {t[r].sz = t[t[r].ch[0]].sz + t[t[r].ch[1]].sz + t[r].cnt;}void rot(int x){    int y = t[x].f, z = t[y].f;    bool f = (t[y].ch[1] == x);    t[y].ch[f] = t[x].ch[f^1];    if(t[y].ch[f]) t[t[y].ch[f]].f = y;    t[x].ch[f^1] = y; t[y].f = x;    t[x].f = z;    if(z) t[z].ch[t[z].ch[1]==y] = x;    Upd(y);}void Spaly(int r, int tp) {    for(int y, z; (y = t[r].f) != tp; rot(r)) {        z = t[y].f;        if(z == tp) continue;        if( (t[z].ch[0] == y) == (t[y].ch[0] == r) ) rot(y);        else rot(r);    }    if(!tp) rt = r; Upd(r);}void Ins(int r, int x) {    int y = 0;    while(r && t[r].v != x) { y = r; r = t[r].ch[x > t[r].v]; }    if(r) ++ t[r].cnt;    else {        r = ++ sz; t[r].sz = t[r].cnt = 1;        t[r].v = x; t[r].f = y; if(y) t[y].ch[x > t[y].v] = r;    }    Spaly(r, 0);}void Find(int v) {    int x = rt; if(!x) return;    while(t[x].ch[v > t[x].v] && t[x].v != v) x = t[x].ch[v > t[x].v];    Spaly(x, 0);}int Ran(int v) {    Find(v);    return t[t[rt].ch[0]].sz;}int Kth(int x){    int y=rt,p;    if(x>t[rt].sz)return 0;    while(1)    {        p=t[y].ch[0];        if(t[p].sz+t[y].cnt<x) {            x-=t[p].sz+t[y].cnt;            y=t[y].ch[1];        }        else if(t[p].sz>=x) y=p;        else return t[y].v;    }}int Nxt(int x, bool f){    Find(x);    if((t[rt].v>x&&f)||(t[rt].v<x&&!f)) return rt;    int p = t[rt].ch[f];    while(t[p].ch[f^1]) p = t[p].ch[!f];    return p;}void Del(int v) {    int p = Nxt(v, 0), s = Nxt(v, 1);    Spaly(p, 0); Spaly(s, p);    p = t[s].ch[0];    if(t[p].cnt > 1) -- t[p].cnt, Spaly(p, 0);    else t[s].ch[0] = 0;}char c, f;inline void GET(int &n) {    n = 0; f = 1;    do {c = getchar(); if(c == '-') f = -1;} while(c > '9' || c < '0');    while(c >= '0' && c <= '9') {n=n*10+c-'0';c=getchar();}    n *= f;}int main() {    freopen("phs.in","r",stdin);    freopen("phs.out","w",stdout);    GET(n);    int opt,x;    Ins(rt, -0x7fffffff); Ins(rt, +0x7fffffff);    for(int i=1; i<=n; i++) {        GET(opt); GET(x);        switch(opt) {            case 1: Ins(rt,x); break;            case 2: Del(x); break;            case 3: printf("%d\n",Ran(x)); break;            case 4: printf("%d\n",Kth(x+1)); break;            case 5: printf("%d\n",t[Nxt(x, 0)].v); break;            case 6: printf("%d\n",t[Nxt(x, 1)].v); break;        }    }    return 0;}

                                                HelenKeller                                                 2016.7.4

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