Submission #1027459

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027459		cnn008	Binaria (CCO23_day1problem1)	C++17	25 / 25	181 ms	36616 KiB

Main

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

#ifdef N_N_C
#include "debug.h"
#else
#define cebug(...) "Arya"
#endif

#define int long long

const int N=1e6+5;
const int mod=1e6+3;

int n,k,a[N],f[N],inv[N],b[N];
int powmod(int a, int k, int m){
   	int ans=1;
    while(k){
        if(k&1) ans=(ans*a)%m;
        a=(a*a)%m;
        k/=2;
    }
    return ans;
}
int C(int n, int k){
	if(n<k || k<0) return 0;
	return f[n]*inv[k]%mod*inv[n-k]%mod;
}
void sol(){
	cin>>n>>k;
	for(int i=k; i<=n; i++) cin>>a[i];
	memset(b,-1,sizeof(b));
	for(int i=k+1; i<=n; i++){
		if(a[i]==a[i-1]+1){
			if(b[i-k]==1){
				cout<<"0";
				return;
			}
			b[i-k]=0;
			b[i]=1;
		}else if(a[i]==a[i-1]){
			if(b[i-k]==1) b[i]=1;
			if(b[i-k]==0) b[i]=0;
			
		}else if(a[i]==a[i-1]-1){
			if(b[i-k]==0){
				cout<<"0";
				return;
			}
			b[i-k]=1;
			b[i]=0;
		}else{
			cout<<"0";
			return;
		}
	}
	for(int i=n; i>=k+1; i--) if(a[i]==a[i-1]) b[i]=b[i-k]=max(b[i],b[i-k]);
	int sz=0,cnt=0;
	for(int i=1; i<=k; i++){
		if(b[i]==-1) sz++;
		if(b[i]==1) cnt++;
	}
	cout<<C(sz,a[k]-cnt);
}
signed main(){
	ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    // freopen(".inp", "r", stdin);
    // freopen(".out", "w", stdout);
    f[0]=1;
    for(int i=1; i<N; i++) f[i]=(f[i-1]*i)%mod;
    inv[0]=1;
    for(int i=1; i<N; i++) inv[i]=powmod(f[i],mod-2,mod);
    int tt=1;
    //cin>>tt; 
    while(tt--){
    	sol();
    }
    cerr << "\nTime elapsed: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 7 / 7