Submission #648623

#	Time	Username	Problem	Language	Result	Execution time	Memory
648623		BackNoob	Skyscraper (JOI16_skyscraper)	C++14	100 / 100	57 ms	15916 KiB

skyscraper

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1)
#define TASK "task"
#define sz(s) (int) (s).size()

using namespace std;
const int mxN = 5e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;

template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}

int n;
int lim;
int a[mxN];
int diff[mxN];
int dp[107][107][1007][3];

void add(int &a, int b)
{
    a += b;
    if(a >= mod)
        a -= mod;
}

void solve()
{
    cin >> n >> lim;
    for(int i = 1; i <= n; i++) cin >> a[i];

    sort(a + 1, a + 1 + n);
    for(int i = 1; i <= n; i++) diff[i] = a[i] - a[i - 1];


    dp[1][1][0][0] = 1;
    dp[1][1][0][1] = 2;
    dp[1][1][0][2] = 1;
    for(int i = 1; i < n; i++) {
        for(int j = 0; j <= i; j++) {
            for(int sum = 0; sum <= lim; sum++) {
                for(int k = 0; k < 3; k++) {
                    if(dp[i][j][sum][k] == 0) continue;
                    int cur = dp[i][j][sum][k];

                    int newsum = sum + (j * 2 - k) * diff[i + 1];
                    if(newsum > lim) continue;
                    // case 1 create comp
                    add(dp[i + 1][j + 1][newsum][k], 1LL * cur * (j + 1 - k) % mod);
                    // fill begin or end
                    if(k < 2) {
                        add(dp[i + 1][j + 1][newsum][k + 1], 1LL * (2 - k) * cur % mod);
                        add(dp[i + 1][j][newsum][k + 1], 1LL * (2 - k) * cur % mod);
                    }

                    // case 2 merge comp
                    if(j > 1) {
                        add(dp[i + 1][j - 1][newsum][k], 1LL * cur * (j - 1) % mod);
                    }

                    // case 3 add
                    add(dp[i + 1][j][newsum][k], 1LL * cur * (j * 2 - k) % mod);
                }
            }
        }
    }

    int res = 0;
    for(int i = 0; i <= lim; i++) add(res, dp[n][1][i][2]);
    cout << res;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen(TASK".inp" , "r" , stdin);
    //freopen(TASK".out" , "w" , stdout);

    int tc = 1;
    //cin >> tc;
    while(tc--) {
    	solve();
    }
    return 0;
}

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