Submission #1281385

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281385		ridarfx	Skyscraper (JOI16_skyscraper)	C++20	15 / 100	125 ms	260776 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
const long long MOD = 1e9 + 7;
const int mxN = 105;
long long dp[mxN][mxN][1005][3];

void solve() {
    int n, L;
    cin >> n >> L;
    vector<int> a(n + 2);
    for (int i = 1; i <= n; i++) cin >> a[i];
    
    sort(a.begin() + 1, a.begin() + n + 1);
    a[n + 1] = 10000; // dummy large number
    
    memset(dp, 0, sizeof(dp));
    dp[0][0][0][0] = 1;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            for (int k = 0; k <= L; k++) {
                for (int m = 0; m <= 2; m++) {
                    long long delta = (2 * j - m) * (a[i + 1] - a[i]);
                    if (delta > k || i + j + 1 - m > n) continue;

                    dp[i][j][k][m] += dp[i - 1][j - 1][k - delta][m];
                    if (m)
                        dp[i][j][k][m] += (3 - m) * dp[i - 1][j - 1][k - delta][m - 1];
                    dp[i][j][k][m] += (2 * j - m) * dp[i - 1][j][k - delta][m];

                    if (m == 1)
                        dp[i][j][k][m] += 2 * j * dp[i - 1][j][k - delta][m - 1];
                    if (m == 2) {
                        if (i == n)
                            dp[i][j][k][m] += dp[i - 1][j][k - delta][m - 1];
                        else if (j > 1)
                            dp[i][j][k][m] += (j - 1) * dp[i - 1][j][k - delta][m - 1];
                    }

                    if (m == 2) {
                        if (i == n)
                            dp[i][j][k][m] += dp[i - 1][j + 1][k - delta][m];
                        else
                            dp[i][j][k][m] += j * (j - 1) * dp[i - 1][j + 1][k - delta][m];
                    } else if (m == 1)
                        dp[i][j][k][m] += j * j * dp[i - 1][j + 1][k - delta][m];
                    else
                        dp[i][j][k][m] += j * (j + 1) * dp[i - 1][j + 1][k - delta][m];

                    dp[i][j][k][m] %= MOD;
                }
            }
        }
    }

    long long ans = 0;
    for (int i = 0; i <= L; i++)
        ans += dp[n][1][i][2];
    cout << ans % MOD << endl;
}

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

• Subtask 1: 0 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80