Submission #46878

#	Time	Username	Problem	Language	Result	Execution time	Memory
46878		qoo2p5	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	389 ms	130784 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int INF = (int) 1e9 + 1e6;
const ll LINF = (ll) 1e18 + 1e9;
const ll MOD = (ll) 1e9 + 7;

#define sz(x) (int) (x).size()
#define mp(x, y) make_pair(x, y)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lb(s, t, x) (int) (lower_bound(s, t, x) - s)
#define ub(s, t, x) (int) (upper_bound(s, t, x) - s)
#define rep(i, f, t) for (auto i = f; i < t; ++(i))
#define per(i, f, t) for (auto i = (f); i >= (t); --(i))

ll power(ll x, ll y, ll mod = MOD) {
    if (y == 0) {
        return 1;
    }
    if (y & 1) {
        return power(x, y - 1, mod) * x % mod;
    } else {
        ll tmp = power(x, y / 2, mod);
        return tmp * tmp % mod;
    }
}

template<typename A, typename B> bool mini(A &x, const B &y) {
    if (y < x) {
        x = y;
        return true;
    }
    return false;
}

template<typename A, typename B> bool maxi(A &x, const B &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

void add(ll &x, ll y) {
    x += y;
    if (x >= MOD) x -= MOD;
    if (x < 0) x += MOD;
}

void run();

#define TASK ""

int main() {
#ifdef LOCAL
    if (strlen(TASK) > 0) {
        cerr << "Reminder: you are using file i/o, filename: " TASK "!" << endl << endl;
    }
#endif
#ifndef LOCAL
    if (strlen(TASK)) {
        freopen(TASK ".in", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
#endif
    cout << fixed << setprecision(12);
    run();
    return 0;
}

// == SOLUTION == //

const int N = 105;
const int L = 1005;

int n, l;
int a[N];
ll dp[N][N][L][3];

void run() {
	cin >> n >> l;
	if (n == 1) {
		cout << "1\n";
		return;
	}
	rep(i, 0, n) {
		cin >> a[i];
	}
	sort(a, a + n);
	
	dp[0][0][0][0] = 1;
	rep(i, 0, n) {
		int w = (i == 0 ? a[i] : a[i] - a[i - 1]);
		
		rep(j, 0, n) {
			rep(t, 0, l) {
				rep(k, 0, 3) {
					int places = j + 1 - k;
					int to_add = 2 * j - k;
					int cost = t + to_add * w;
					ll cur = dp[i][j][t][k];
					
					if (cost <= l) {
						add(dp[i + 1][j + 1][cost][k], (cur * places) % MOD);
						if (j > 0) {
							add(dp[i + 1][j][cost][k], (cur * to_add) % MOD);
						}
						if (j >= 2) {
							add(dp[i + 1][j - 1][cost][k], (cur * (j - 1)) % MOD);
						}
						
						if (k == 0) {
							add(dp[i + 1][j + 1][cost][1], (cur * 2) % MOD);
							if (j > 0) {
								add(dp[i + 1][j][cost][1], (cur * 2) % MOD);
							}
						} else if (k == 1) {
							add(dp[i + 1][j + 1][cost][2], cur);
							if (j > 0) {
								add(dp[i + 1][j][cost][2], cur);
							}
						}
					}
				}
			}
		}
	}
	
	ll ans = 0;
	rep(i, 0, l + 1) {
		add(ans, dp[n][1][i][2]);
	}
	cout << ans << "\n";
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".in", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".out", "w", stdout);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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