poj1442 Black Box treap

来源：互联网发布：千牛卖家版mac不能用编辑：程序博客网时间：2024/05/01 19:13
N个数，在插入第B[i]个数之后，查询当前集合中第i小的数是多少。treap模板题...
#include <iostream>#include <cstdio>#include <cmath>#include <cstring>#include <cstdlib>using namespace std;typedef long long ll;const int maxn=101000;int pre[maxn];int ch[maxn][2];int size[maxn];int ct[maxn];int pri[maxn];int key[maxn];int tot,root;int cmp(int a,int b){    if (a==b) return -1;    if (a<b) return 0;    else return 1;}struct TREAP{    void init()    {        root=0;        memset(pre,0,sizeof pre);        memset(ch,0,sizeof ch);        memset(ct,0,sizeof ct);        memset(size,0,sizeof size);        tot=0;    }    void pushup(int r)    {        size[r]=size[ch[r][0]]+size[ch[r][1]]+ct[r];    }    void rotate(int x,int kind)    {        int k=ch[x][kind^1];        ch[x][kind^1]=ch[k][kind];        pre[ch[k][kind]]=x;        ch[k][kind]=x;        pre[k]=pre[x];        if (pre[x])        {            ch[pre[x]][ch[pre[x]][1]==x]=k;        }        else root=k;        pre[x]=k;        pushup(x);        pushup(k);    }    void newnode(int &r,int father,int k)    {        r=++tot;        pre[r]=father;        pri[r]=rand();        size[r]=1;        ct[r]=1;        key[r]=k;        ch[r][0]=ch[r][1]=0;    }    void insert(int &rt,int x,int father)    {        if (rt==0)        {            newnode(rt,father,x);        }        else        {            int d=cmp(x,key[rt]);            if (d==-1)            {                ct[rt]++;                size[rt]++;            }            else            {                insert(ch[rt][d],x,rt);                pushup(rt);                if (pri[ch[rt][d]]>pri[rt]) rotate(rt,d^1);            }        }    }    void print(int r)    {        if (r==0) return;        print(ch[r][0]);        for (int i=1; i<=ct[r]; i++)        printf("%d ",key[r]);        print(ch[r][1]);    }    void printpri(int r)    {        if (r==0) return;        print(ch[r][0]);        printf("%d ",pri[r]);        print(ch[r][1]);    }    int select(int k)    {        int rt=root;        while(true)        {            if (k<=size[ch[rt][0]]) rt=ch[rt][0];            else if (k<=size[ch[rt][0]]+ct[rt]) break;            else k-=(size[ch[rt][0]]+ct[rt]),rt=ch[rt][1];        }        return rt;    }}treap;int n,m;int a[100600];int b[100600];int main(){//    freopen("in.txt","r",stdin);    while(~scanf("%d%d",&n,&m))    {        treap.init();        for (int i=1; i<=n; i++)        scanf("%d",&a[i]);        for (int i=1; i<=m; i++)        scanf("%d",&b[i]);        int pt=1;        for (int i=1; i<=n; i++)        {            treap.insert(root,a[i],0);//            treap.print(root);//            puts("");            while (i==b[pt])            {                int ans=treap.select(pt);                cout<<key[ans]<<endl;//                treap.del(ans);//                treap.insert(root,key[ans]+1,0);                pt++;            }        }    }    return 0;}
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