Тема: корнячка❤️❤️❤️❤️❤️ на с++

 #include <bits/stdc++.h> 
using namespace std; 
 
struct Query { 
    int l, r, index; 
}; 
 
bool compare(const Query &a, const Query &b, int block_size) { 
    if (a.l / block_size == b.l / block_size) { 
        return (a.l / block_size) % 2 == 0 ? a.r < b.r : a.r > b.r; 
    } 
    return a.l < b.l; 
} 
 
void add(int x, vector<int> &count, int &current_answer) { 
    if (count[x] == 0) { 
        current_answer++; 
    } 
    count[x]++; 
} 
 
void remove(int x, vector<int> &count, int &current_answer) { 
    if (count[x] == 1) { 
        current_answer--; 
    } 
    count[x]--; 
} 

int main() { 
    ios::sync_with_stdio(0); 
    cin.tie(0); 
 
    int n; 
    cin >> n; 
 
    vector<int> arr(n); 
    for (int i = 0; i < n; i++) { 
        cin >> arr[i]; 
    }
    int q; 
    cin >> q; 
    vector<Query> queries(q); 
    for (int i = 0; i < q; i++) { 
        cin >> queries[i].l >> queries[i].r; 
        queries[i].l--;  // переводим в 0-индексацию 
        queries[i].r--; 
        queries[i].index = i; 
    }
    int MAX_VALUE = *max_element(arr.begin(), arr.end()); 
    // Создаем вектор для хранения количества вхождений чисел 
    vector<int> count(MAX_VALUE + 1, 0); 
    int block_size = sqrt(n); 
    sort(queries.begin(), queries.end(), [&block_size](Query &a, Query &b) { 
        return compare(a, b, block_size); 
    }); 
    vector<int> answers(q); 
    int current_answer = 0; 
    int current_l = 0, current_r = -1; 
    for (const auto &query : queries) { 
        while (current_r < query.r) 
            add(arr[++current_r], count, current_answer); 
        while (current_r > query.r) 
            remove(arr[current_r--], count, current_answer); 
        while (current_l < query.l) 
            remove(arr[current_l++], count, current_answer); 
        while (current_l > query.l) 
            add(arr[--current_l], count, current_answer); 
 
        answers[query.index] = current_answer; 
    }
    for (int i = 0; i < q; i++) { 
        cout << answers[i] << "\n"; 
    } 
    return 0; 
}