Submission #1168467

#	Time	Username	Problem	Language	Result	Execution time	Memory
1168467		nguyn	Skyscraper (JOI16_skyscraper)	C++20	15 / 100	1 ms	656 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;

#define ll long long 
#define F first
#define S second
#define pb push_back 
#define pii pair<int,int>

const int N = 105;
const int L = 1005; 
const ll mod = 1e9 + 7; 
const int inf  = 1e4; 

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

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

signed main(){
    ios_base::sync_with_stdio(false) ; 
    cin.tie(0) ; cout.tie(0) ; 
    if (fopen("INP.INP" ,"r")) {
        freopen("INP.INP" ,"r" , stdin) ;
        freopen("OUT.OUT" , "w" , stdout) ;
    }
    cin >> n >> l;
    for (int i = 1; i <= n; i++) {
        cin >> a[i]; 
    }
    sort(a + 1, a + 1 + n);
    a[n + 1] = inf;
    f[0][0][0][0] = 1; 
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            for (int k = 0; k <= l; k++) {
                for (int m = 0; m <= 2; m++) {
                    ll tmp = 1ll * (2 * j - m) * (a[i + 1] - a[i]); 
                    if (tmp > k || j - m + 1 > n - i) continue; 

                    add(f[i][j][k][m], f[i - 1][j - 1][k - tmp][m]); 

                    if (m) {
                        add(f[i][j][k][m], 1ll * (3 - m) * f[i - 1][j - 1][k - tmp][m - 1] % mod); 
                    }

                    add(f[i][j][k][m], 1ll * (2 * j - m) * f[i - 1][j][k - tmp][m] % mod);

                    if (m == 1) {
                        add(f[i][j][k][m], 1ll * 2 * j * f[i - 1][j][k - tmp][m - 1] % mod);
                    }
                    if (m == 2) {
                        if (i == n) {
                            add(f[i][j][k][m], f[i - 1][j][k - tmp][m - 1]); 
                        }
                        else if (j > 1) {
                            add(f[i][j][k][m], 1ll * (j - 1) * f[i - 1][j][k - tmp][m - 1] % mod); 
                        }
                    }

                    if (m == 2) {
                        if (i == n) {
                            add(f[i][j][k][m], f[i - 1][j + 1][k - tmp][m]); 
                        }
                        else {
                            add(f[i][j][k][m], 1ll * j * (j - 1) * f[i - 1][j + 1][k - tmp][m] % mod);
                        }
                    }
                    else if (m == 1) {
                        add(f[i][j][k][m], 1ll * j * j * f[i - 1][j + 1][k - tmp][m] % mod); 
                    }
                    else {
                        add(f[i][j][k][m], 1ll * j * (j + 1) * f[i - 1][j + 1][k - tmp][m] % mod); 
                    }
                }
            }
        }
    }
    ll res = 0;
    for (int i = 0; i <= l; i++) {
        add(res, f[n][1][i][2]); 
    }
    cout << res; 
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |         freopen("INP.INP" ,"r" , stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:30:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |         freopen("OUT.OUT" , "w" , stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80