【模板】Splay

Splay适用于维护序列
用起来很方便，而且很好打

参考博客：Splay-总结

#include<cstdio>#include<algorithm>#define Rec rt->s[1]->s[0]using namespace std;const int maxn=500005,INF=0x3f3f3f3f;int n,q,a[maxn];char str[15];struct node{    node* s[2];    int x,size,sum,same,lm,rm,ma;    bool flip;    node(int h=0,node *son=NULL){s[0]=s[1]=son;x=sum=lm=rm=ma=h;size=1;same=INF;flip=0;}    int cmp(int &k){        if (k<=s[0]->size) return 0;        if (k>s[0]->size+1) {k-=s[0]->size+1;return 1;}        return -1;    }    void maintain(){        size=s[0]->size+s[1]->size+1;        sum=s[0]->sum+s[1]->sum+x;        lm=max(s[0]->lm,max(s[0]->sum+x,s[0]->sum+x+s[1]->lm));        rm=max(s[1]->rm,max(s[1]->sum+x,s[1]->sum+x+s[0]->rm));        ma=max(max(max(s[0]->ma,s[1]->ma),max(s[0]->rm+x,s[1]->lm+x)),max(x,s[0]->rm+x+s[1]->lm));    }    void add_same(int k) {x=same=k;sum=k*size;lm=rm=ma=(k>0?sum:k);}    void add_flip() {swap(s[0],s[1]);swap(lm,rm);flip^=1;}    void pushdown(){        if (same!=INF) s[0]->add_same(same),s[1]->add_same(same),same=INF;        if (flip) s[0]->add_flip(),s[1]->add_flip(),flip=0;    }}nil;typedef node* P_node;P_node null,rt;void splay_init(){    rt=null=&nil;    null->s[0]=null->s[1]=null;    null->size=null->x=null->sum=0;    null->lm=null->rm=null->ma=-INF;    null->same=INF;null->flip=0;}void recycle(P_node &x){    if (x==null) return;    recycle(x->s[0]);recycle(x->s[1]);    delete x;}void rot(P_node &x,int d){    P_node k=x->s[d^1];x->s[d^1]=k->s[d];k->s[d]=x;    x->maintain();k->maintain();x=k;}void splay(P_node &x,int k){    x->pushdown();    int d1=x->cmp(k);    if (d1!=-1){        x->s[d1]->pushdown();        int d2=x->s[d1]->cmp(k);        if (d2!=-1){            splay(x->s[d1]->s[d2],k);            if (d1==d2) rot(x,d1^1),rot(x,d1^1);else             rot(x->s[d1],d2^1),rot(x,d1^1);        }else rot(x,d1^1);    }}P_node build(int l,int r){    if (l>r) return null;    int mid=l+r>>1;P_node p=new node(a[mid],null);    p->s[0]=build(l,mid-1);p->s[1]=build(mid+1,r);    p->maintain();    return p;}void get_rec(P_node &x,int l,int r) {splay(x,l-1);splay(x->s[1],r-l+2);}void print(P_node x){    if (x==null) return;x->pushdown();x->maintain();    print(x->s[0]);    printf("%d ",x->x);    print(x->s[1]);}int main(){    splay_init();    //do something...    return 0;}