uva 11991 Easy Problem from Rujia Liu?

const int INF =0x3f3f3f3f;
const int maxn= 1000000+10   ;
//const int maxm=    ;
//by yskysker123

vector<int>G[maxn];  //答案里面用了 map<int,vector<int> > a.
int n,m;
int main()
{
    int x;
    while(~scanf("%d%d",&n,&m) )
    {
            for(int i=1;i<=n;i++)
            G[i].clear();

        for(int i=1;i<=n;i++)
        {
            scanf("%d",&x);
            int m=G[x].size();
            G[x].push_back(i);

        }
        int k,v;
        for(int i=1;i<=m;i++)
        {
            scanf("%d%d",&k,&v);
            int m=G[v].size();
            if(m<k)  puts("0");
            else printf("%d\n",G[v][k-1]);
        }

    }

    return 0;
}

#include<cstdio>
#include<string>
#include<cstring>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<climits>
#include<queue>
#include<vector>
#include<map>
#include<sstream>
#include<set>
#include<stack>
#include<utility>
#pragma comment(linker, "/STACK:102400000,102400000")
#define PI 3.1415926535897932384626
#define eps 1e-10
#define sqr(x) ((x)*(x))
#define FOR0(i,n)  for(int i=0 ;i<(n) ;i++)
#define FOR1(i,n)  for(int i=1 ;i<=(n) ;i++)
#define FORD(i,n)  for(int i=(n) ;i>=0 ;i--)
#define  lson   num<<1,le,mid
#define rson    num<<1|1,mid+1,ri
#define MID   int mid=(le+ri)>>1
#define zero(x)((x>0? x:-x)<1e-15)
#define mk    make_pair
#define _f     first
#define _s     second

using namespace std;
//const int INF=    ;
typedef long long ll;
//const ll inf =1000000000000000;//1e15;
//ifstream fin("input.txt");
//ofstream fout("output.txt");
//fin.close();
//fout.close();
//freopen("a.in","r",stdin);
//freopen("a.out","w",stdout);