「模板」 01 Trie实现平衡树功能

#include <cstdio>
#include <cstring>
const int MAXN=100010<<5,INF=10000000;
int n;
class Trie
{
    public:
        Trie(void)
        {
            cnt=1;
            memset(s,0,sizeof s);
        }
        void Insert(int x)
        {
            int k=1,p=x+INF;
            for(int i=30,t;~i;++s[k=s[k].c[t]].size,--i)
                if(!s[k].c[t=p>>i&1])
                    s[k].c[t]=++cnt;
            s[k].v=x;
        }
        void Erase(int x)
        {
            int k=1,p=x+INF;
            for(int i=30;~i;--s[k=s[k].c[p>>i&1]].size,--i);
        }
        int Rank(int x)
        {
            int k=1,p=x+INF,ans=1;
            for(int i=30,t;~i;--i,k=s[k].c[t])
                if(t=p>>i&1)
                    ans+=s[s[k].c[0]].size;
            return ans;
        }
        int Find(int x)
        {
            int k=1,ans=0;
            for(int i=30,t,f;~i;--i,k=s[k].c[t])
                if(t=(x>(f=s[s[k].c[0]].size)))
                    x-=f;
            return s[k].v;
        }
        int Pre(int x)
        {
            return Find(Rank(x)-1);
        }
        int Next(int x)
        {
            return Find(Rank(x+1));
        }
    private:
        int cnt;
        struct node
        {
            int v,size,c[2];
        }s[MAXN];
}T;
int main(int argc,char *argv[])
{
    freopen("testdata.in","r",stdin);
    freopen("my.out","w",stdout);
    scanf("%d",&n);
    for(int i=1,opt,x;i<=n;++i)
    {
        scanf("%d %d",&opt,&x);
        switch(opt)
        {
            case 1:
                T.Insert(x);
                break;
            case 2:
                T.Erase(x);
                break;
            case 3:
                printf("%d\n",T.Rank(x));
                break;
            case 4:
                printf("%d\n",T.Find(x));
                break;
            case 5:
                printf("%d\n",T.Pre(x));
                break;
            case 6:
                printf("%d\n",T.Next(x));
                break;
        }
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}