1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>

using namespace std;

const int MAXN = 10000005;
const int B = 3162;

bool has_stone[MAXN];
vector<int> small_primes;

int cnt[450][B + 5];
int max_p[450];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n, q;
    if (!(cin >> n >> q)) return 0;

    vector<bool> is_p(B + 1, true);
    //sito erastotenesa
    for (int i = 2; i <= B; i++) {
        if (is_p[i]) {
            small_primes.push_back(i);
            for (int j = i * i; j <= B; j += i) is_p[j] = false;
        }
    }

    int total_stones = 0;
    vector<int> active_stones;
    vector<int> results;
    results.reserve(q);

    for (int i = 0; i < q; i++) {
        int x;
        cin >> x;

        bool adding = !has_stone[x];
        has_stone[x] = adding;
        total_stones += (adding ? 1 : -1);

        int current_max = 0;

        for (size_t j = 0; j < small_primes.size(); j++) {
            int p = small_primes[j];
            int rem = x % p;

            if (adding) {
                cnt[j][rem]++;
                max_p[j] = max(max_p[j], cnt[j][rem]);
            }
            else {
                if (cnt[j][rem] == max_p[j]) {
                    cnt[j][rem]--;
                    int new_max = 0;
                    for (int k = 0; k < p; k++) {
                        new_max = max(new_max, cnt[j][k]);
                    }
                    max_p[j] = new_max;
                }
                else {
                    cnt[j][rem]--;
                }
            }
            current_max = max(current_max, max_p[j]);
        }

        if (current_max < n / B + 2 && total_stones > 0) {
            if (adding) {
                active_stones.push_back(x);
            }
            else {
                active_stones.erase(find(active_stones.begin(), active_stones.end(), x));
            }

            int max_large = 0;
            for (int stone : active_stones) {
                if (stone == x) continue;
                int dist = abs(stone - x);

                if (dist > B && (n / dist + 1 > current_max)) {
                    int count = 0;
                    int rem = x % dist;
                    for (int pos = (rem == 0 ? dist : rem); pos <= n; pos += dist) {
                        if (has_stone[pos]) count++;
                    }
                    max_large = max(max_large, count);
                }
            }
            current_max = max(current_max, max_large);
        }
        else if (total_stones > 0) {
            active_stones.clear();
        }

        if (total_stones == 0) current_max = 0;
        results.push_back(current_max);
    }
    for (int res : results) {
        cout << res << "\n";
    }

    return 0;
}