Submission #896538

#	Time	Username	Problem	Language	Result	Execution time	Memory
896538		borisAngelov	Beautiful row (IZhO12_beauty)	C++17	100 / 100	1860 ms	231356 KiB

beauty

#include <bits/stdc++.h>

using namespace std;

const int maxn = 20;
const int maxMask = (1 << maxn);

int n;

int a[maxn + 5];

bool areNeighbours[maxn + 5][maxn + 5];

long long dp[maxMask + 5][maxn + 5];
bool bl[maxMask + 5][maxn + 5];

int cnt2(int x)
{
    int res = 0;

    while (x != 0)
    {
        if (x % 2 == 1)
        {
            ++res;
        }

        x /= 2;
    }

    return res;
}

int cnt3(int x)
{
    int res = 0;

    while (x != 0)
    {
        if (x % 3 == 1)
        {
            ++res;
        }

        x /= 3;
    }

    return res;
}

bool check(int x, int y)
{
    int x2 = cnt2(x);
    int x3 = cnt3(x);
    int y2 = cnt2(y);
    int y3 = cnt3(y);

    return x2 == y2 || x3 == y3;
}

long long f(int mask, int last)
{
    if (mask == (1 << n) - 1)
    {
        return 1;
    }

    if (bl[mask][last] == true)
    {
        return dp[mask][last];
    }

    bl[mask][last] = true;

    long long result = 0;

    for (int i = 0; i < n; ++i)
    {
        if ((mask & (1 << i)) == 0 && areNeighbours[i][last] == true)
        {
            result += f((mask | (1 << i)), i);
        }
    }

    return dp[mask][last] = result;
}

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n;

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

    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j < n; ++j)
        {
            if (i != j && check(a[i], a[j]) == true)
            {
                areNeighbours[i][j] = true;
            }
        }
    }

    long long ans = 0;

    for (int i = 0; i < n; ++i)
    {
        ans += f((1 << i), i);
    }

    cout << ans << endl;

    return 0;
}

• Subtask 1: 100 / 100