poj 2892 hdu 1540 不错的线段树题

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<sstream>
#include<string>
#include<climits>
#include<stack>
#include<set>
#include<bitset>
#include<cmath>
#include<deque>
#include<map>
#include<queue>
#define iinf 2000000000
#define linf 1000000000000000000LL
#define dinf 1e200
#define eps 1e-5
#define all(v) (v).begin(),(v).end()
#define sz(x)  x.size()
#define pb push_back
#define mp make_pair
#define lng long long
#define sqr(a) ((a)*(a))
#define pii pair<int,int>
#define pll pair<lng,lng>
#define pss pair<string,string>
#define pdd pair<double,double>
#define X first
#define Y second
#define pi 3.14159265359
#define ff(i,xi,n) for(int i=xi;i<=(int)(n);++i)
#define ffd(i,xi,n) for(int i=xi;i>=(int)(n);--i)
#define ffl(i,r) for(int i=head[r];i!=-1;i=edge[i].next)
#define cc(i,j) memset(i,j,sizeof(i))
#define two(x)			((lng)1<<(x))
#define N 51000
#define M 1000000
#define lson l , mid , rt << 1
#define rson mid + 1 , r , rt << 1 | 1
#define Mod  n
#define Pmod(x) (x%Mod+Mod)%Mod
using namespace std;
typedef vector<int>  vi;
typedef vector<string>  vs;
typedef unsigned int uint;
typedef unsigned lng ulng;
template<class T> inline void checkmax(T &x,T y){if(x<y) x=y;}
template<class T> inline void checkmin(T &x,T y){if(x>y) x=y;}
template<class T> inline T Min(T x,T y){return (x>y?y:x);}
template<class T> inline T Max(T x,T y){return (x<y?y:x);}
template<class T> T gcd(T a,T  b){return (a%b)==0?b:gcd(b,a%b);}
template<class T> T lcm(T a,T b){return a*b/gcd(a,b);}
template<class T> T Abs(T a){return a>0?a:(-a);}
template<class T> inline T lowbit(T n){return (n^(n-1))&n;}
template<class T> inline int countbit(T n){return (n==0)?0:(1+countbit(n&(n-1)));}
template<class T> inline bool isPrimeNumber(T n)
{if(n<=1)return false;for (T i=2;i*i<=n;i++) if (n%i==0) return false;return true;}
int n,sum[N<<2],m;
bool is[N];
inline void pushup(int rt)
{
    sum[rt]=sum[rt<<1]+sum[rt<<1|1];
}
void build(int l,int r,int rt)
{
    if(l==r)
    {
        sum[rt]=0;
        return ;
    }
    int mid=(l+r)>>1;
    build(lson);
    build(rson);
    pushup(rt);
}
int query(int L,int R,int l,int r,int rt)
{
    if (L<=l&&r<=R)
    {
        return sum[rt];
    }
    int ret=0;
    int mid=(l+r)>>1;
    if(L<=mid) ret+=query(L,R,lson);
    if(R>mid) ret+=query(L,R,rson);
    return ret;
}
int query(int k,int l,int r,int rt)
{
    if(l==r)
    {
        return l;
    }
    int mid=(l+r)>>1;
    if(k<=sum[rt<<1])
   return  query(k,lson);
    else
   return    query(k-sum[rt<<1],rson);
}
void update(int p,int add,int l,int r,int rt)
{
    if(l==r)
    {
        sum[rt]+=add;
        return ;
    }
    int mid=(l+r)>>1;
    if(p<=mid) update(p,add,lson);
    else update(p,add,rson);
    pushup(rt);
}
int main()
{
   while(scanf("%d%d",&n,&m)==2)
   {
       char opt;
       int pre[N],top=0;
       cc(is,0);
       build(0,n+1,1);
       update(n+1,1,0,n+1,1);
       ff(i,1,m)
       { getchar();
           scanf("%c",&opt);
           if(opt=='R')
           {
               if(is[pre[top]]) update(pre[top],-1,0,n+1,1),is[pre[top--]]=0;
           }
           else
           if(opt=='D')
           {
               int id;
               scanf("%d",&id);
               pre[++top]=id;
              if(!is[pre[top]]) update(id,1,0,n+1,1),is[pre[top]]=1;
           }
           else
           {
               int id;
               scanf("%d",&id);
               int su=query(0,id,0,n+1,1);
               int id1,id2;
               id1=query(su,0,n+1,1);
               id2=query(su+1,0,n+1,1);
               if(id1==id)
               printf("0\n");
               else
               printf("%d\n",id2-id1-1);
           }
       }
   }
    return 0;
}