제출 #1030890

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1030890		MarwenElarbi	캥거루 (CEOI16_kangaroo)	C++17	100 / 100	10 ms	31936 KiB

kangaroo

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ii pair<int,int>
template <class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int nax=2e3+5;
const int MOD=1e9+7;
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
long long dp[nax][nax];
int main()
{
    optimise;
    int n,s,t; 
    cin>>n>>s>>t;
    if(n<=2){
        cout <<0<<endl;
        return 0;
    }
    if(s>t) swap(s,t);
    memset(dp,0,sizeof dp);
    dp[0][0] = 1;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 0; j <= n-i+1; ++j)
        {
            if(i<s){
                dp[i][j]+= 1ll * dp[i-1][j+1] * (j+1) * (j);
                dp[i][j]+= (j ? dp[i-1][j-1] : 0);
            }else if(i==s){
                dp[i][j]+= 1ll * dp[i-1][j+1] * (j+1);
                dp[i][j]+= dp[i-1][j];
            }else if(i<t){
                dp[i][j]+= 1ll * dp[i-1][j+1] * (j+1) * (j+1);
                dp[i][j]+= (j ? dp[i-1][j-1] : 0);
            }else if(i==t){
                dp[i][j]+= 1ll* dp[i-1][j+1] * (j+1);
                dp[i][j]+= dp[i-1][j];
            }else if(i>t){
                dp[i][j]+= 1ll * dp[i-1][j+1] * (j+2) * (j+1);
                dp[i][j]+= (j ? dp[i-1][j-1] : 0);
            }
            dp[i][j]%=MOD;
        }
    }
    cout <<dp[n-1][0]<<endl;
}

• Subtask 1: 6 / 6
• Subtask 2: 30 / 30
• Subtask 3: 15 / 15
• Subtask 4: 49 / 49