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Submission #915303

# Submission time Handle Problem Language Result Execution time Memory
915303 2024-01-23T16:15:04 Z bachhoangxuan Ruins 3 (JOI20_ruins3) C++17
100 / 100
 513 ms 8272 KB 
// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
- insert(x),erase(x)
- find_by_order(k): return iterator to the k-th smallest element
- order_of_key(x): the number of elements that are strictly smaller
*/

#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<int,pii>
#define mpp make_pair
#define fi first
#define se second
const int inf=1e18;
const int mod=1e9+7;
const int maxn=1205;
const int bl=650;
const int maxs=655;
const int maxm=200005;
const int maxq=1000005;
const int maxl=25;
const int maxa=1000000;
const int root=3;
int power(int a,int n){
    int res=1;
    while(n){
        if(n&1) res=res*a%mod;
        a=a*a%mod;n>>=1;
    }
    return res;
}
const int iroot=power(3,mod-2);
const int base=131;

int fac[maxn],dfac[maxn],inv[maxn];
int C(int n,int k){
    if(k>n || k<0 || n<0) return 0;
    return fac[n]*dfac[k]%mod*dfac[n-k]%mod;
}
void combi(int n){
    fac[0]=1;
    for(int i=1;i<=n;i++) fac[i]=fac[i-1]*i%mod;
    dfac[n]=power(fac[n],mod-2);
    for(int i=n;i>=1;i--){
        dfac[i-1]=dfac[i]*i%mod;
        inv[i]=dfac[i]*fac[i-1]%mod;
    }
}

int n,dp[maxn][maxn];
bool c[maxn];

void solve(){
    cin >> n;
    combi(2*n);
    for(int i=1;i<=n;i++){
        int x;cin >> x;
        c[x]=1;
    }
    int a=0,b=0;
    dp[2*n+1][0]=1;
    for(int i=2*n;i>=1;i--){
        for(int j=b;j<=a+1;j++){
            if(!c[i]){
                dp[i][j]=(dp[i][j]+dp[i+1][j]*(j-b))%mod;
            }
            else{
                for(int k=1;k<=j;k++){
                    dp[i][j]=(dp[i][j]+dp[i+1][j-k]*C(a-j+k,k-1)%mod*C(2*k,k)%mod*fac[k-1]%mod)%mod;
                }
                dp[i][j]=(dp[i][j]+dp[i+1][j])%mod;
            }
            //cout << dp[i][j] << ' ';
        }
        //cout << '\n';
        if(c[i]) a++;
        else b++;
    }
    cout << dp[1][n]*power((mod+1)/2,n)%mod << '\n';
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    int test=1;//cin >> test;
    while(test--) solve();
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2392 KB Output is correct
10 Correct 1 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 1 ms 2396 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2392 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2396 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 1 ms 2512 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2392 KB Output is correct
18 Correct 2 ms 2396 KB Output is correct
19 Correct 1 ms 2536 KB Output is correct
20 Correct 1 ms 2392 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 1 ms 2396 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2392 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2396 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 1 ms 2512 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2392 KB Output is correct
18 Correct 2 ms 2396 KB Output is correct
19 Correct 1 ms 2536 KB Output is correct
20 Correct 1 ms 2392 KB Output is correct
21 Correct 53 ms 5456 KB Output is correct
22 Correct 42 ms 5204 KB Output is correct
23 Correct 42 ms 5200 KB Output is correct
24 Correct 83 ms 5588 KB Output is correct
25 Correct 1 ms 860 KB Output is correct
26 Correct 39 ms 5208 KB Output is correct
27 Correct 26 ms 3392 KB Output is correct
28 Correct 8 ms 5100 KB Output is correct
29 Correct 1 ms 344 KB Output is correct
30 Correct 513 ms 8020 KB Output is correct
31 Correct 442 ms 7404 KB Output is correct
32 Correct 500 ms 7764 KB Output is correct
33 Correct 503 ms 8272 KB Output is correct
34 Correct 448 ms 7428 KB Output is correct
35 Correct 491 ms 7744 KB Output is correct
36 Correct 506 ms 7980 KB Output is correct