oj.uz

Submission #1041980

# Submission time Handle Problem Language Result Execution time Memory
1041980 2024-08-02T11:35:46 Z hotboy2703 Ruins 3 (JOI20_ruins3) C++17
100 / 100
 219 ms 10076 KB 
#include<bits/stdc++.h>
using ll = long long;
using namespace std;
#define pll pair <ll,ll>
#define fi first
#define se second
#define MP make_pair
#define sz(a) (ll((a).size()))
#define BIT(mask,i) (((mask) >> (i))&1)
#define MASK(i) (1LL << (i))
const ll INF = 1e9;
const ll MAXN = 1210;
ll dp[MAXN][MAXN];
ll fac[2*MAXN],fiv[2*MAXN];
const ll MOD = 1e9+7;
ll p(ll x,ll y){
    ll res = 1;
    for (;y;y>>=1,x=x*x%MOD)if (y&1)res=res*x%MOD;
    return res;
}
ll inv(ll x){
    return p(x,MOD-2);
}
ll C(ll k,ll n){
    if (k > n || k < 0)return 0;
    return fac[n] * fiv[k] % MOD * fiv[n-k] % MOD;
}
ll ways[MAXN];
bool ok[2*MAXN];
int main(){
    ios_base::sync_with_stdio(0);cin.tie(nullptr);
    ll n;
    cin>>n;
    for (ll i = 1;i <= n;i ++){
        ll x;cin>>x;
        ok[x] = 1;
    }
    fac[0] = 1;
    for (ll i = 1;i <= 2*n;i ++)fac[i] = fac[i-1]*i%MOD;
    fiv[2*n] = inv(fac[2*n]);
    for (ll i = 2*n-1;i >= 0;i --)fiv[i] = fiv[i+1]*(i+1)%MOD;
    for (ll i = 0;i <= n;i ++)ways[i] = (C(i,2*i) * fac[i-1])%MOD;
    // cout<<ways[1]<<' '<<ways[2]<<'\n';
    ll a,b;dp[2*n+1][0] = 1;
    a=b=0;
    for (ll i = 2 * n;i >= 1;i --){
        if (ok[i]){
            a++;
            for (ll j = b;j <= a;j ++){
                for (ll k = b;k < j;k ++){
                    dp[i][j] += dp[i+1][k] * C(j - k - 1,a - k - 1) % MOD * ways[j-k];
                    dp[i][j] %= MOD;
                }
                dp[i][j] += dp[i+1][j];
                dp[i][j] %= MOD; 
            }
            
        }
        else{
            b++;
            for (ll j = b;j <= a;j ++){
                dp[i][j] = dp[i+1][j] * (j-(b-1)) % MOD;
            }
        }
        // for (ll j = 0;j <= n;j ++)cout<<dp[i][j]<<' ';
        // cout<<'\n';
    }
    cout<<dp[1][n] * inv(p(2,n)) % MOD;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct
6 Correct 0 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 0 ms 2396 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct
6 Correct 0 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 0 ms 2396 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 0 ms 2520 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 0 ms 2396 KB Output is correct
16 Correct 0 ms 2396 KB Output is correct
17 Correct 0 ms 2392 KB Output is correct
18 Correct 0 ms 2524 KB Output is correct
19 Correct 0 ms 2396 KB Output is correct
20 Correct 0 ms 2396 KB Output is correct

Subtask #3
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct
6 Correct 0 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 0 ms 2396 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 0 ms 2520 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 0 ms 2396 KB Output is correct
16 Correct 0 ms 2396 KB Output is correct
17 Correct 0 ms 2392 KB Output is correct
18 Correct 0 ms 2524 KB Output is correct
19 Correct 0 ms 2396 KB Output is correct
20 Correct 0 ms 2396 KB Output is correct
21 Correct 2 ms 7768 KB Output is correct
22 Correct 3 ms 5212 KB Output is correct
23 Correct 2 ms 10076 KB Output is correct
24 Correct 4 ms 7772 KB Output is correct
25 Correct 0 ms 604 KB Output is correct
26 Correct 2 ms 8808 KB Output is correct
27 Correct 1 ms 4700 KB Output is correct
28 Correct 2 ms 8796 KB Output is correct
29 Correct 0 ms 348 KB Output is correct
30 Correct 219 ms 9568 KB Output is correct
31 Correct 108 ms 9040 KB Output is correct
32 Correct 157 ms 8640 KB Output is correct
33 Correct 197 ms 9556 KB Output is correct
34 Correct 103 ms 9044 KB Output is correct
35 Correct 159 ms 8532 KB Output is correct
36 Correct 188 ms 9552 KB Output is correct