HDU 4585(Shaolin-Treap的lower_bound&upper_bound操作)

题意：有n个数，每个数进来时求出与它与它最接近的数的编号（多个答案选数小的）

模板测试

#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <functional>
#include <cstdlib>
#include <queue>
#include <stack>
#include <set>
using namespace std;
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
typedef long long ll;
typedef unsigned long long ull;
ll mul(ll a,ll b){return (a*b)%F;}
ll add(ll a,ll b){return (a+b)%F;}
ll sub(ll a,ll b){return (a-b+llabs(a-b)/F*F+F)%F;}
void upd(ll &a,ll b){a=(a%F+b%F)%F;}
int read()
{
    int x=0,f=1; char ch=getchar();
    while(!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}
    while(isdigit(ch)) { x=x*10+ch-'0'; ch=getchar();}
    return x*f;
} 
#define
int n;
struct treap{
    ll rnd[MAXN],v[MAXN];
    int size[MAXN],l[MAXN],r[MAXN],cnt;
    void mem() {
        MEM(size) MEM(rnd) MEM(l) MEM(r) MEM(v)
        cnt=0;
    }
    void update(int x)
    {
        size[x]=size[l[x]]+size[r[x]]+1;
    }
    void rturn(int &k)
    {
        int t=l[k];l[k]=r[t];r[t]=k;update(k);update(t);k=t;
    }
    void lturn(int &k)
    {
        int t=r[k];r[k]=l[t];l[t]=k;update(k);update(t);k=t;
    }
    int union2(int x,int y) { //new node = unoin2(x,y)
        if (!x) return y;if (!y) return x;
        if (size[x]<size[y]) swap(x,y);
        union2(x,l[y]);union2(x,r[y]);
        insert(x,v[y],y);
        return x;
    }
    void insert(int &x,ll rank,int y=0) //insert (x,newnode(rank),0) or insert(x,node[y])
    {
        if(!x)
        {
            if (!y) x=++cnt;else {
                x=y;
            }
            v[x]=rank; l[x]=r[x]=0;
            rnd[x]=rand();size[x]=1;
            return ;
        }
        size[x]++;
        if(v[x]<rank)
        {
            insert(r[x],rank,y);
            if(rnd[r[x]]<rnd[x])lturn(x);
        }
        else if (v[x]>rank)
        {
            insert(l[x],rank,y);
            if(rnd[l[x]]<rnd[x]) rturn(x);
        }return ;
    }
    // return the pointer
    int lower_bound(int x,ll rank) {
        int ans=-1;
        if (!x) return ans;
        if (v[x]<=rank) {
            ans=lower_bound(r[x],rank);
            if (ans==-1) ans=x;
        } else ans=lower_bound(l[x],rank);
        return ans;
    }
    int upper_bound(int x,ll rank) {
        int ans=-1;
        if (!x) return ans;
        if (v[x]>rank) {
            ans=upper_bound(l[x],rank);
            if (ans==-1) ans=x;
        } else ans=upper_bound(r[x],rank);
        return ans;
    }
    void pri(int x){
        if (l[x]) pri(l[x]);
        cout<<v[x]<<' ';
        if (r[x]) pri(r[x]);
    }
}T;
int id[MAXN];
int main() {
    // freopen("hdu4585.in","r",stdin);

    while(scanf("%d",&n)==1&&n) {
        T.mem();
        int rot=0;
        T.insert(rot,1e9);id[1]=1;
        Fork(i,2,n+1) {
            ll ans=-1;
            ll a=read(),b=read();
            id[i]=a;
            int p1=T.lower_bound(rot,b);
            int p2=T.upper_bound(rot,b);
            if (p1==-1||p2==-1) ans=max(p1,p2); 
            else if (b-T.v[p1]<=T.v[p2]-b) ans=p1;
            else ans=p2;
            printf("%lld %d\n",a,id[ans]);
            T.insert(rot,b);
        }
    }  
    return 0;
}