Poklon (palomar, vector)

#include <iostream>
#include <vector>
#include <map>
using namespace std;

map<int,int> id;
int dar_id(const int &num)
{
    if (!id[num])
        id[num] = id.size();

    return id[num]-1;
}

vector<int> cant;
void add (const int &num)
{
    if (num == cant.size() )
        cant.push_back(1);
    else cant[num]++;
}

int main()
{
    vector<int> v;
    vector< vector<int> > DP;
    int n, q;
    cin>>n>>q;

    v.resize(n);
    DP.resize(n+1);

    for(int i=0; i<n; i++)
    {
        cin>>v[i];
        v[i] = dar_id(v[i]);
    }

    DP[0] = cant;
    for(int i=1; i<=n; i++)
    {
        add( v[i-1] );
        DP[i] = cant;
    }

    int a, b;
    vector<int> canta, cantb;
    for(int i=0; i<q; i++)
    {
        cin>>a>>b;

        canta = DP[a-1];
        cantb = DP[b];
        int c = 0;

        for(int i=0; i<canta.size(); i++)
            cantb[i] -= canta[i];

        for(int i=0; i<cantb.size(); i++)
            if (cantb[i] == 2)
                c++;

        cout<<c<<endl;
    }
    return 0;
}