Submission #615701

#	Time	Username	Problem	Language	Result	Execution time	Memory
615701		nohaxjustsoflo	Gondola (IOI14_gondola)	C++17	60 / 100	21 ms	15964 KiB

gondola

#include <bits/stdc++.h>
#include <iostream>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<ll,null_type,less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> order_set;
mt19937 mt_rand(chrono::high_resolution_clock::now().time_since_epoch().count());
//uniform_int_distribution<int> gen; ///(min, max)
//int random() {return gen(mt_rand);}
const int mxN=1e6+5;
const int mod=1e9+7;
const int mxlogN=40;
const int mxK=26;
const int inf=2e9;
const int K=600;
#include "gondola.h"

int valid(int n, int a[])
{
    for(int i=0; i<n; i++)
    {
        if(a[i]<=n)
        {
            for(int j=i+1; j-i<n; j++) if(a[j%n]<=n&&a[j%n]!=(a[i]+j-i-1)%n+1) return 0;
            break;
        }
    }
    sort(a,a+n);
    for(int i=0; i+1<n; i++) if(a[i]==a[i+1]) return 0;
    return 1;
}

//----------------------

int replacement(int n, int a[], int b[])
{
    int c[n];
    iota(c,c+n,1);
    for(int i=0; i<n; i++)
    {
        if(a[i]<=n)
        {
            for(int j=i; j-i<n; j++) c[j%n]=(a[i]+j-i-1)%n+1;
            break;
        }
    }
    int w[250001];
    for(int i=1; i<=250000; i++) w[i]=-1;
    for(int i=0; i<n; i++) w[a[i]]=c[i];
    for(int i=249999; i>n; i--) if(!~w[i]) w[i]=w[i+1];
    int j=0;
    for(int i=n+1; i<=250000; i++)
    {
        if(!~w[i]) break;
        if(w[i]==w[i-1]) b[j++]=i-1;
        else b[j++]=w[i];
    }
    return j;
}

//----------------------

ll powb(ll a, ll x)
{
    ll ret=1;
    a%=mod;
    while(x)
    {
        if(x&1)ret=ret*a%mod;
        x>>=1;
        a=a*a%mod;
    }
    return ret;
}
ll inv(ll x)
{
    return powb(x, mod-2);
}
ll f[mxN], finv[mxN];
ll chose(ll a, ll b)
{
    if(a<0||a>b) return 0;
    return f[b]*finv[a]%mod*finv[b-a]%mod;
}

int countReplacement(int n, int a[])
{
    if(!valid(n, a)) return 0;
    sort(a,a+n);

    f[0]=1;
    for(int i=1; i<mxN; i++) f[i]=f[i-1]*i%mod;
    finv[mxN-1]=inv(f[mxN-1]);
    for(int i=mxN-2; i>=0; i--) finv[i]=finv[i+1]*(i+1)%mod;

    ll ways=1;
    bool ok=1;
    for(int i=0; i<n; i++)
    {
        if(a[i]>n)
        {
            int sz;
            if(i) sz=a[i]-max(n,a[i-1]);
            else sz=a[i]-n;
            ways=ways*powb(n-i,sz-1)%mod;
        }
        else ok=0;
    }
    if(ok) while(1);
    return ways;
}
/*
int countReplacement(int n, int a[])
{
    if(!valid(n, a)) return 0;

    int c[n];
    iota(c,c+n,1);
    bool ok=1;
    for(int i=0; i<n; i++)
    {
        if(a[i]<=n)
        {
            for(int j=i; j-i<n; j++) c[j%n]=(a[i]+j-i-1)%n+1;
            ok=0;
            break;
        }
    }
    int w[250001];
    for(int i=1; i<=250000; i++) w[i]=-1;
    for(int i=0; i<n; i++) w[a[i]]=c[i];
    set<int> s;
    for(int i=249999; i>n; i--)
    {
        if(!~w[i]) w[i]=w[i+1];
        else s.insert(w[i]);
    }
    ll ways=1;
    for(int i=n+1; i<=250000; i++)
    {
        if(!~w[i]) break;
        if(w[i]==w[i-1]) ways=ways*(ll)s.size()%mod;
        else s.erase(w[i-1]);
    }
    if(ok) for(int i=2; i<=n; i++) ways=ways*i%mod;
    return ways;
}

int main()
{
    int n; cin >> n;
    int a[n];
    for(int i=0; i<n; i++) cin >> a[i];
    cout << countReplacement(n,a);
}
*/
/*
5 4 3
0 1 2
0 2 3
3 2 1
2 4 4
1 3 4
*/

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 10 / 10
• Subtask 4: 5 / 5
• Subtask 5: 10 / 10
• Subtask 6: 20 / 20
• Subtask 7: 5 / 5
• Subtask 8: 0 / 15
• Subtask 9: 0 / 15
• Subtask 10: 0 / 10