Submission #40733

#	Time	Username	Problem	Language	Result	Execution time	Memory
40733		Alexa2001	Skyscraper (JOI16_skyscraper)	C++14	100 / 100	468 ms	4068 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

const int Nmax = 103, Kmax = 1003;
const int Mod = 1e9 + 7;
typedef long long ll;

int N, K, i, j, k, F, S, new_k, a[Nmax];
int now[Nmax][Kmax][2][2], old[Nmax][Kmax][2][2];

void add_to(int &x, int y, int z)
{
    x = (x + (ll)y*z) % Mod;
}

int main()
{
    // freopen("input", "r", stdin);

    cin >> N >> K;
    for(i=1; i<=N; ++i) cin >> a[i];
    sort(a+1, a+N+1);
    for(i=1; i<N; ++i) a[i] = a[i+1] - a[i];

    now[0][0][1][1] = now[0][0][0][1] = now[0][0][1][0] = now[0][0][0][0] = 1;
    for(i=1; i<N; ++i)
    {
        memcpy(old, now, sizeof(now));
        memset(now, 0, sizeof(now));

        for(j=0; j<=N; ++j)
            for(k=0; k<=K; ++k)
                for(F=0; F<2; ++F)
                    for(S=0; S<2; ++S)
                    {
                        new_k = k + a[i] * (2 * j + F + S);
                        if(new_k > K) continue;

                        add_to(now[j+1][new_k][F][S], j, old[j][k][F][S]);
                        add_to(now[j][new_k][F][S], 2*j, old[j][k][F][S]);
                        if(j) add_to(now[j-1][new_k][F][S], j, old[j][k][F][S]);

                        if(F)
                        {
                            add_to(now[j+1][new_k][1][S], 1, old[j][k][F][S]);
                            add_to(now[j][new_k][1][S], 1, old[j][k][F][S]);
                            add_to(now[j+1][new_k][0][S], 1, old[j][k][F][S]);
                            add_to(now[j][new_k][0][S], 1, old[j][k][F][S]);
                        }

                        if(S)
                        {
                            add_to(now[j+1][new_k][F][1], 1, old[j][k][F][S]);
                            add_to(now[j][new_k][F][1], 1, old[j][k][F][S]);
                            add_to(now[j+1][new_k][F][0], 1, old[j][k][F][S]);
                            add_to(now[j][new_k][F][0], 1, old[j][k][F][S]);
                        }
                    }
    }

    int ans = 0;
    for(i=0; i<=K; ++i) add_to(ans, 1, now[0][i][0][0]);
    cout << ans << '\n';

    return 0;
}

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