Submission #873930

#	Time	Username	Problem	Language	Result	Execution time	Memory
873930		noiaint	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	215 ms	347728 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

#define file ""

#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()

#define getbit(x, i) (((x) >> (i)) & 1)
#define bit(x) (1LL << (x))
#define popcount __builtin_popcountll

mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) {
    return l + rd() % (r - l + 1);
}

const int N = 1e6 + 5;
const int mod = (int)1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int oo = 1e9;
const long long ooo = 1e18;

template<class X, class Y> bool mini(X &a, Y b) {
    return a > b ? (a = b, true) : false;
}
template<class X, class Y> bool maxi(X &a, Y b) {
    return a < b ? (a = b, true) : false;
}
void add(int &a, int b) {
    a += b;
    if (a >= mod) a -= mod;
    if (a < 0) a += mod;
}

int n, L;
int a[N];
long long f[105][105][1005][2][2];

long long calc(int i, int j, int s, int l, int r) {
    int news = s + (j * 2 + l + r) * (a[i] - a[i - 1]);
    if (news > L) return 0;
    if (j < 0) return 0;
    if (i == n) return j == 0;

    long long &res = f[i][j][s][l][r];
    if (res != -1) return res;
    res = 0;

    res += calc(i + 1, j, news, 1, r); // append to the left
    res += calc(i + 1, j - 1, news, 1, r) * j; // append to the left and merge

    res += calc(i + 1, j, news, l, 1); // append to the right
    res += calc(i + 1, j - 1, news, l, 1) * j; // append to the right and merge

    res += calc(i + 1, j + 1, news, l, r); // new one
    res += calc(i + 1, j, news, l, r) * j * 2; // append
    res += calc(i + 1, j - 1, news, l, r) * j * (j - 1); // merge

    res %= mod;
    return res;
}

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

    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);

    cin >> n >> L;
    for (int i = 1; i <= n; ++i)
        cin >> a[i];
    sort(a + 1, a + n + 1);
    a[0] = a[1];

    memset(f, -1, sizeof f);
    cout << calc(1, 0, 0, 0, 0);

    return 0;
}

/*

*/

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