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Submission #204018

# Submission time Handle Problem Language Result Execution time Memory
204018 2020-02-23T20:25:08 Z mahmoudbadawy Kangaroo (CEOI16_kangaroo) C++17
6 / 100
 5 ms 504 KB 
#include <bits/stdc++.h>

using namespace std;

const int N=2005,MOD=1e9+7;

long long mem[N][N];
int n,a,b;

int main()
{
	cin >> n >> a >> b;
	mem[1][1]=1;
	for(int i=2;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			if(i==a||i==b)
			{
				mem[i][j]=mem[i-1][j]+mem[i-1][j-1];
				if(mem[i][j]>=MOD) mem[i][j]-=MOD;
				continue;
			}
			mem[i][j]=mem[i-1][j-1]*(j-(i>a)+(i>b)); // add a new component
			mem[i][j]%=MOD;
			mem[i][j]+=mem[i-1][j+1]*j; // combine two existing components;
			mem[i][j]%=MOD;
		}
	}
	cout << mem[n][1] << endl;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 5 ms 376 KB Output is correct

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 5 ms 376 KB Output is correct
4 Incorrect 5 ms 504 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 5 ms 376 KB Output is correct
4 Incorrect 5 ms 504 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #4
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 5 ms 376 KB Output is correct
4 Incorrect 5 ms 504 KB Output isn't correct
5 Halted 0 ms 0 KB -