8402.cpp

#include <bits/stdc++.h>
using namespace std;

const int MAXN = 100000 + 5;

int arr[MAXN];
int freq[MAXN];
long long suf[MAXN];

void generateArray(int* arr, int n, int m, int seed) {
    unsigned x = seed;
    for (int i = 1; i <= n; i++) {
        x ^= x << 13;
        x ^= x >> 17;
        x ^= x << 5;
        arr[i] = x % m + 1;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m, seed;
    cin >> n >> m >> seed;

    generateArray(arr, n, m, seed);

    // 計算頻率
    for (int i = 1; i <= n; i++) {
        freq[arr[i]]++;
    }

    // suffix sum: suf[x] = count of numbers >= x
    for (int i = m; i >= 1; i--) {
        suf[i] = suf[i + 1] + freq[i];
    }

    long long ans = 0;

    for (int x = 1; x <= m; x++) {
        long long c = suf[x];
        if (c == 0) continue;

        // 找最大 2^k ≤ c
        long long p = 1;
        while (p * 2 <= c) p *= 2;

        ans = max(ans, p * x);
    }

    cout << ans << "\n";

    return 0;
}