SPOJ - DQUERY

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <stack>
#include <cctype>
#include <queue>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <climits>
#define lson rt<<1,l,mid
#define rson rt<<1|1,mid+1,r
#define fi first
#define se second
#define ping(x,y) ((x-y)*(x-y))
#define mst(x,y) memset(x,y,sizeof(x))
#define mcp(x,y) memcpy(x,y,sizeof(y))
using namespace std;
#define gamma 0.5772156649015328606065120
#define MOD 1000000007
#define inf 0x3f3f3f3f
#define N 55005
#define maxn 30010
typedef pair<int,int> PII;
typedef long long LL;
LL read(){
    LL x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=(x<<3)+(x<<1)+ch-‘0‘;ch=getchar();}
    return x*f;
}

int n,m,k,ans,v,a[N],b[N],L,R;
int loc[N],root[N<<1],sz;
map<int,int>M;
struct Node{int l,r,v;}seg[N*25];
void update(int &rot,int rt,int l,int r,int pos){
    seg[++sz]=seg[rot],rot=sz;
    seg[rot].v+=v;
    if(l==r)return;
    int mid=l+r>>1;
    if(pos<=mid)update(seg[rot].l,lson,pos);
    else update(seg[rot].r,rson,pos);
}
int query(int rt,int l,int r,int x,int y,int rot){
    if(x<=l&&r<=y)return seg[rot].v;
    int mid=l+r>>1;
    int temp=0;
    if(x<=mid)temp+=query(lson,x,y,seg[rot].l);
    if(y>mid) temp+=query(rson,x,y,seg[rot].r);
    return temp;
}
int main(){
    int i,j,group,x,y,Case=0;
    n=read();
    for(i=1;i<=n;++i)a[i]=read(),b[i]=a[i];
    sort(b+1,b+n+1);
    int _n=unique(b+1,b+n+1)-b-1;
    for(i=1;i<=_n;++i)M[b[i]]=i;
    for(i=1;i<=n;++i){
        v=1;
        if(!loc[M[a[i]]])update(root[i]=root[i-1],1,1,n,i);
        else{
            int temp;
            v=-1;update(temp=root[i-1],1,1,n,loc[M[a[i]]]);
            v=1;update(root[i]=temp,1,1,n,i);
        }
        loc[M[a[i]]]=i;
    }
    m=read();
    for(i=1;i<=m;++i){
        x=read(),y=read();
        printf("%d\n",query(1,1,n,x,y,root[y]));
    }
    return 0;
}