Submission #589387

#	Time	Username	Problem	Language	Result	Execution time	Memory
589387		Loki_Nguyen	Skyscraper (JOI16_skyscraper)	C++14	100 / 100	1097 ms	24376 KiB

skyscraper

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ull unsigned long long
#define pb push_back
#define pll pair<int, pii>
#define pii pair<int, int>
#define fi first
#define se second
using namespace std;
const int N = 102;
const int M = 10002;
const int mod = 1e9 + 7;
const int base = 75;
const ll inf = 1e12;
int n, t, tong;
int k, m, a[N], b[N], dp[2][N][M][3];
int ans;
void add(int& x, int y)
{
    x += y;
    if (x >= mod)
        x -= mod;
}
void sol()
{
    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        cin >> a[i], b[i] = i;
    if (n == 1)
    {
        cout << 1 << '\n';
        return;
    }
    sort(a + 1, a + 1 + n);
    reverse(a + 1, a + 1 + n);
    dp[1][1][a[1] * 2][0] = 1;
    dp[1][1][a[1]][1] = 2;
    for (int i = 1; i < n; i++)
    {
        memset(dp[(i&1)^1], 0, sizeof(dp[(i&1)^1]));
        for (int j = 1; j <= i; j++)
        {
            for (int p = 0; p < M; p++)
            {
                for (int q = 0; q < 3; q++)
                {
                    if (dp[i&1][j][p][q] == 0)
                        continue;
                    if (p + a[i + 1] * 2 < M)
                        add(dp[(i&1)^1][j + 1][p + a[i + 1] * 2][q], 1ll * dp[i&1][j][p][q] * (j + 1 - q) % mod);
                    if (q < 2 && p + a[i + 1] < M)
                        add(dp[(i&1)^1][j + 1][p + a[i + 1]][q + 1], 1ll * dp[i&1][j][p][q] * (2 - q) % mod);
                    add(dp[(i&1)^1][j][p][q], 1ll * dp[i&1][j][p][q] * (2 * j - q) % mod);
                    if (q < 2 && p >= a[i + 1])
                        add(dp[(i&1)^1][j][p - a[i + 1]][q + 1], 1ll * dp[i&1][j][p][q] * (2 - q) % mod);
                    if (j > 1 && p >= a[i + 1] * 2)
                        add(dp[(i&1)^1][j - 1][p - a[i + 1] * 2][q], 1ll * dp[i&1][j][p][q] * (j - 1) % mod);
                }
            } 
        }
    }
    for (int i = 0; i <= k; i++)
        add(ans, dp[n&1][1][i][2]);
    cout << ans << '\n';
}
int main()
{
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);
#define task "tests"
    if (fopen(task ".inp", "r"))
    {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    int test = 1;
    // cin >> test;
    while (test-- > 0)
        sol();
    return 0;
} 

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:75:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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