Submission #851558

#	Time	Username	Problem	Language	Result	Execution time	Memory
851558		khanhphucscratch	Binaria (CCO23_day1problem1)	C++14	25 / 25	69 ms	34640 KiB

Main

#include<bits/stdc++.h>
#define int long long
using namespace std;
int a[1000001], fact[1000001], inv[1000001], color[1000001];
const int mod = 1e6+3;
int power(int a, int b)
{
    if(b == 0) return 1;
    int ans = power(a, b/2);
    ans = (ans * ans)%mod;
    if(b%2 == 1) ans = (ans * a)%mod;
    return ans;
}
int C(int k, int n)
{
    if(k > n || k < 0) return 0;
    return (fact[n] * ((inv[k] * inv[n-k])%mod))%mod;
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, k;
    cin>>n>>k;
    fact[0] = inv[0] = 1;
    for(int i = 1; i <= n; i++) fact[i] = (fact[i-1] * i)%mod;
    inv[n] = power(fact[n], mod-2);
    for(int i = n-1; i >= 1; i--) inv[i] = (inv[i+1] * (i+1))%mod;
    for(int i = 1; i <= n-k+1; i++) cin>>a[i];
    for(int i = 1; i <= n; i++) color[i] = 2;
    for(int i = n-k; i >= 1; i--){
        if(abs(a[i] - a[i+1]) > 1){cout<<0; return 0;}
        if(a[i] == a[i+1]) color[i] = color[i+k];
        else if(a[i] > a[i+1]){
            if(color[i+k] == 1){cout<<0; return 0;}
            color[i] = 1;
        }
        else{
            if(color[i+k] == 0){cout<<0; return 0;}
            color[i] = 0;
        }
    }
    /*for(int i = 1; i <= n; i++) cout<<color[i]<<" ";
    cout<<'\n';*/
    int re = 0;
    for(int i = 1; i <= k; i++){a[1] -= (color[i] == 1); re += (color[i] == 2);}
    cout<<C(a[1], re);
}

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