Submission #110559

# Submission time Handle Problem Language Result Execution time Memory
110559 2019-05-11T07:16:52 Z gumball Kangaroo (CEOI16_kangaroo) C++14
0 / 100
29 ms 32376 KB
#include<bits/stdc++.h>
typedef long long ll;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
ll n,S,T,d[2020][2020],mo=1e9+7;
ll depe(ll aa,ll bb)
{
	if(aa==(n+1)&&bb==1)return 1;
	if(aa==(n+1))return 0;
	if(bb<=0)return 0;
	ll ret=d[aa][bb];
	if(ret!=-1)return ret;
	ret=0;
	ll ujg=0;
	if(aa>S)ujg++;
	if(aa>T)ujg++;
	if(aa==S||aa==T)
	{
		ret=(depe(aa+1,bb)+depe(aa+1,bb-1))%mo;
	}	
	else
	{	
		ret=(ret+depe(aa+1,bb+1)*(bb+1-ujg))%mo;
		ret=(ret+depe(aa+1,bb-1)*(bb-1))%mo;
	}
	return d[aa][bb]=ret;
}
int main()
{
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>n>>S>>T;
	memset(d,-1,sizeof(d));
	cout<<depe(1,1)<<"\n";
}	
# Verdict Execution time Memory Grader output
1 Correct 28 ms 32376 KB Output is correct
2 Incorrect 29 ms 32248 KB Output isn't correct
# Verdict Execution time Memory Grader output
1 Correct 28 ms 32376 KB Output is correct
2 Incorrect 29 ms 32248 KB Output isn't correct
# Verdict Execution time Memory Grader output
1 Correct 28 ms 32376 KB Output is correct
2 Incorrect 29 ms 32248 KB Output isn't correct
# Verdict Execution time Memory Grader output
1 Correct 28 ms 32376 KB Output is correct
2 Incorrect 29 ms 32248 KB Output isn't correct