Submission #57380

#	Time	Username	Problem	Language	Result	Execution time	Memory
57380		mraron	Kangaroo (CEOI16_kangaroo)	C++14	6 / 100	3 ms	696 KiB

kangaroo

/*
ID: noszaly1
TASK: {TASK}
LANG: C++11               
*/

//Noszály Áron 10o Debreceni Fazekas Mihály Gimnázium

#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<cassert>
#include<cassert>
#include<unordered_map>
#include<unordered_set>
#include<functional>
#include<queue>
#include<stack>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<sstream>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<numeric>
using namespace std;

#define all(x) (x).begin(), (x).end()
#define pb push_back
#define xx first
#define yy second
#define sz(x) (int)(x).size()
#define gc getchar
#define IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define mp make_pair

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const double PI=acos(-1);

template<typename T> T getint() {
	T val=0;
	char c;
	
	bool neg=false;
	while((c=gc()) && !(c>='0' && c<='9')) {
		neg|=c=='-';
	}

	do {
		val=(val*10)+c-'0';
	} while((c=gc()) && (c>='0' && c<='9'));

	return val*(neg?-1:1);
}

#define int ll

int dp[2001][2001];
const int mod=1e9+7;

main() {
	IO;
	int n, s, f;
	cin>>n>>s>>f;
	if(n==2) {
		cout<<"1\n";
	}
	
	if(s>f) swap(s,f);
	
	dp[1][1]=1;
	for(int i=2;i<=n;++i) {
			//cerr<<i<<": ";
			for(int j=1;j<=i;++j) {
				if(i<s) {
					dp[i][j]=(dp[i-1][j-1]+dp[i-1][j+1]*(j+1)*j)%mod;
				}else 
				if(i==s) {
					dp[i][j]=(dp[i-1][j-1]+j*dp[i-1][j])%mod;
				}else 
				if(s<i && i<f) {
					dp[i][j]=(dp[i-1][j-1]+dp[i-1][j+1]*j*j)%mod;
				}else 
				if(i==f) {
					dp[i][j]=(dp[i-1][j-1]+(j-1)*dp[i-1][j])%mod;
				}else 
				if(f<i && i!=n) {
					dp[i][j]=(dp[i-1][j-1]+dp[i-1][j+1]*(2*j+(j-1)*(j-1)-2))%mod;
				}else if(i==n) {
					dp[i][j]=(dp[i-1][j-1]+dp[i-1][j+1]*(2*j+(j-1)*(j-1)-1))%mod;
				}
				//cerr<<dp[i][j]<<" \n"[i==j];
			}
	}
	
	
	cout<<dp[n][1]<<"\n";
	return 0;
}

Compilation message (stderr)

kangaroo.cpp:66:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

• Subtask 1: 6 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49