<span>codeforces703D Mishka and Interesting sum（区间偶数异或）</span>

/* ***********************************************
Author        :devil
************************************************ */
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <stack>
#include <map>
#include <string>
#include <cmath>
#include <stdlib.h>
#define inf 0x3f3f3f3f
#define LL long long
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define dep(i,a,b) for(int i=a;i>=b;i--)
#define ou(a) printf("%d\n",a)
#define pb push_back
#define mkp make_pair
template<class T>inline void rd(T &x){char c=getchar();x=0;while(!isdigit(c))c=getchar();while(isdigit(c)){x=x*10+c-'0';c=getchar();}}
#define IN freopen("in.txt","r",stdin);
#define OUT freopen("out.txt","w",stdout);
using namespace std;
const int mod=1e9+7;
const int N=1e6+10;
int a[N],sum[N],c[N],ans[N],n,q,l,r;
vector<pair<int,int> >eg[N];
map<int,int>last;
int lowbit(int x)
{
    return x&(-x);
}
int add(int i,int val)
{
    for(;i<=n;i+=lowbit(i)) c[i]^=val;
}
int summ(int i)
{
    int ret=0;
    for(;i>0;i-=lowbit(i)) ret^=c[i];
    return ret;
}
int main()
{
    rd(n);
    rep(i,1,n) rd(a[i]),sum[i]=sum[i-1]^a[i];
    rd(q);
    rep(i,1,q)
    {
        rd(l),rd(r);
        eg[r].pb(mkp(l,i));
    }
    int cnt=0;
    rep(i,1,n)
    {
        if(last.count(a[i])) add(last[a[i]],a[i]);
        add(i,a[i]);
        last[a[i]]=i;
        for(int j=0;j<eg[i].size();j++)
        {
            int tmp=sum[i]^sum[eg[i][j].first-1];
            tmp^=(summ(i)^summ(eg[i][j].first-1));
            ans[eg[i][j].second]=tmp;
            cnt++;
        }
        if(cnt==q) break;
    }
    rep(i,1,q) ou(ans[i]);
    return 0;
}