oj.uz

Submission #30654

# Submission time Handle Problem Language Result Execution time Memory
30654 2017-07-26T02:29:38 Z zscoder Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 73 ms 17820 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
 
typedef long long ll;
typedef pair<int,ll> ii;
typedef vector<int> vi;
typedef long double ld; 
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<ll>::iterator sit;
typedef map<ll,ll>::iterator mit;

const int MOD = 1e9 + 7;

void add(int &a, int b)
{
	a+=b;
	while(a>=MOD) a-=MOD;
}

int mult(int a, int b)
{
	return (a*1LL*b)%MOD;
}

int dp[2001][2001];

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n,s,e;
	cin>>n>>s>>e;
	s--; e--;
	if(s==0)
	{
		dp[0][0]=1;
	}
	else if(e==0)
	{
		dp[0][0]=1;
	}
	else
	{
		dp[0][1]=1;
	}
	for(int i=0;i<n-1;i++)
	{
		for(int j=0;j<n;j++)
		{
			if(dp[i][j]!=0)
			{
				//cerr<<i<<' '<<j<<' '<<dp[i][j]<<'\n';
				int v=dp[i][j];
				if(i+1==n-1)
				{
					add(dp[i+1][j],v);
					continue;
				}
				if(i+1==s)
				{
					//just add
					add(dp[i+1][j],v);
					//combine with free
					if(j>=1) add(dp[i+1][j-1],mult(j,v));
				}
				else if(i+1==e)
				{
					//just add
					add(dp[i+1][j],v);
					//combine with free
					if(j>=1) add(dp[i+1][j-1],mult(j,v));
				}
				else
				{
					//new component
					add(dp[i+1][j+1],v);
					//merge two free components
					if(j>=2) add(dp[i+1][j-1],mult(j*(j-1),v));
					//append to starting component
					if(i+1>=s)
					{
						//add(dp[i+1][j],v);
						//merge starting with free
						if(j>=1)
						{
							add(dp[i+1][j-1],mult(j,v));
						}
					}
					//append to ending component
					if(i+1>=e)
					{
						//add(dp[i+1][j],v);
						//merge ending with free
						if(j>=1)
						{
							add(dp[i+1][j-1],mult(j,v));
						}
					}
				}
			}
		}
	}
	cout<<dp[n-1][0]<<'\n';
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17820 KB Output is correct
2 Correct 0 ms 17820 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17820 KB Output is correct
2 Correct 0 ms 17820 KB Output is correct
3 Correct 0 ms 17820 KB Output is correct
4 Correct 0 ms 17820 KB Output is correct
5 Correct 0 ms 17820 KB Output is correct
6 Correct 0 ms 17820 KB Output is correct
7 Correct 0 ms 17820 KB Output is correct
8 Correct 0 ms 17820 KB Output is correct
9 Correct 0 ms 17820 KB Output is correct
10 Correct 0 ms 17820 KB Output is correct
11 Correct 0 ms 17820 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17820 KB Output is correct
2 Correct 0 ms 17820 KB Output is correct
3 Correct 0 ms 17820 KB Output is correct
4 Correct 0 ms 17820 KB Output is correct
5 Correct 0 ms 17820 KB Output is correct
6 Correct 0 ms 17820 KB Output is correct
7 Correct 0 ms 17820 KB Output is correct
8 Correct 0 ms 17820 KB Output is correct
9 Correct 0 ms 17820 KB Output is correct
10 Correct 0 ms 17820 KB Output is correct
11 Correct 0 ms 17820 KB Output is correct
12 Correct 0 ms 17820 KB Output is correct
13 Correct 0 ms 17820 KB Output is correct
14 Correct 0 ms 17820 KB Output is correct
15 Correct 0 ms 17820 KB Output is correct
16 Correct 0 ms 17820 KB Output is correct
17 Correct 0 ms 17820 KB Output is correct
18 Correct 0 ms 17820 KB Output is correct
19 Correct 0 ms 17820 KB Output is correct
20 Correct 0 ms 17820 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17820 KB Output is correct
2 Correct 0 ms 17820 KB Output is correct
3 Correct 0 ms 17820 KB Output is correct
4 Correct 0 ms 17820 KB Output is correct
5 Correct 0 ms 17820 KB Output is correct
6 Correct 0 ms 17820 KB Output is correct
7 Correct 0 ms 17820 KB Output is correct
8 Correct 0 ms 17820 KB Output is correct
9 Correct 0 ms 17820 KB Output is correct
10 Correct 0 ms 17820 KB Output is correct
11 Correct 0 ms 17820 KB Output is correct
12 Correct 0 ms 17820 KB Output is correct
13 Correct 0 ms 17820 KB Output is correct
14 Correct 0 ms 17820 KB Output is correct
15 Correct 0 ms 17820 KB Output is correct
16 Correct 0 ms 17820 KB Output is correct
17 Correct 0 ms 17820 KB Output is correct
18 Correct 0 ms 17820 KB Output is correct
19 Correct 0 ms 17820 KB Output is correct
20 Correct 0 ms 17820 KB Output is correct
21 Correct 6 ms 17820 KB Output is correct
22 Correct 6 ms 17820 KB Output is correct
23 Correct 9 ms 17820 KB Output is correct
24 Correct 59 ms 17820 KB Output is correct
25 Correct 53 ms 17820 KB Output is correct
26 Correct 59 ms 17820 KB Output is correct
27 Correct 73 ms 17820 KB Output is correct
28 Correct 33 ms 17820 KB Output is correct