Submission #1255245

#	Time	Username	Problem	Language	Result	Execution time	Memory
1255245		dbence	Skyscraper (JOI16_skyscraper)	C++20	100 / 100	109 ms	120336 KiB

skyscraper

#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define len(x) (x).size()
#define lsb(x) (x) & (-x)
#define l(x) (x << 1) + 1
#define r(x) (x << 1) + 2
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define lb lower_bound
#define ub upper_bound
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

template <typename T>
void print(T t) {
    cout << t << "\n";
}

template <typename T, typename... Args>
void print(T t, Args ...args) {
    cout << t << " ";
    print(args...);
}

const int N = 101;
const int M = 1001;
const int mod = 1e9 + 7;
int n, h, a[N], dp[N][N][M][3];

int calc(int i, int j, int k, int f) {
    if (f >= 3) {
        return 0;
    }
    if (j == 0) {
        return 0;
    }
    if (k > h) {
        return 0;
    }
    if (i > n) {
        return j == 1 && f == 2;
    }
    if (dp[i][j][k][f] != -1) {
        return dp[i][j][k][f];
    }
    int res = 0, remk = k + (a[i] - a[i - 1]) * (2 * j - f);
    res += 1ll * calc(i + 1, j + 1, remk, f) * (j + 1 - f) % mod;
    res += 1ll * calc(i + 1, j + 1, remk, f + 1) * (2 - f) % mod;
    res %= mod;
    res += 1ll * calc(i + 1, j - 1, remk, f) * (j - 1) % mod;
    res %= mod;
    res += 1ll * calc(i + 1, j, remk, f) * (2 * j - f) % mod;
    res %= mod;
    res += 1ll * calc(i + 1, j, remk, f + 1) * (2 - f) % mod;
    res %= mod;
    return dp[i][j][k][f] = res;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> h;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    sort(a + 1, a + n + 1);

    memset(dp, -1, sizeof dp);
    cout << (calc(2, 1, 0, 0) + 2ll * calc(2, 1, 0, 1) + calc(2, 1, 0, 2)) % mod << "\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80