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Submission #878955

# Submission time Handle Problem Language Result Execution time Memory
878955 2023-11-25T18:14:02 Z misteg168 Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 27 ms 31620 KB 
#include<bits/stdc++.h>
#define mod 1000000007
using namespace std;

typedef long long ll;

int n, a, b;
inline int add(int a, int b)
{
    if(!b)
        return a;
    int x = a+b;
    if(x >= mod)
        x -= mod;
    else
        if(x < 0)
            x += mod;
    return x;
}
ll mul(ll a, ll b)
{
    return (a * b) % mod;
}
ll dp[2002][2002];
int main()
{
    cin >> n >> a >> b;
    dp[1][1] = 1;
    for(int i = 2; i <= n; ++i)
        for(int j = 1; j <= n; ++j)
        {
            if(i == a || i == b)
                dp[i][j] = add(dp[i-1][j-1], dp[i-1][j]);
            else
                dp[i][j] = add(mul(dp[i-1][j+1], j), mul(dp[i-1][j-1], j - (i > a) - (i > b)));
        }
    cout << dp[n][1];
    return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 2 ms 2648 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 2 ms 2648 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct
13 Correct 3 ms 4536 KB Output is correct
14 Correct 1 ms 4440 KB Output is correct
15 Correct 1 ms 4444 KB Output is correct
16 Correct 1 ms 4444 KB Output is correct
17 Correct 3 ms 4604 KB Output is correct
18 Correct 2 ms 4440 KB Output is correct
19 Correct 1 ms 4444 KB Output is correct
20 Correct 1 ms 4444 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 2 ms 2648 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct
13 Correct 3 ms 4536 KB Output is correct
14 Correct 1 ms 4440 KB Output is correct
15 Correct 1 ms 4444 KB Output is correct
16 Correct 1 ms 4444 KB Output is correct
17 Correct 3 ms 4604 KB Output is correct
18 Correct 2 ms 4440 KB Output is correct
19 Correct 1 ms 4444 KB Output is correct
20 Correct 1 ms 4444 KB Output is correct
21 Correct 7 ms 10584 KB Output is correct
22 Correct 4 ms 12636 KB Output is correct
23 Correct 5 ms 12636 KB Output is correct
24 Correct 27 ms 31596 KB Output is correct
25 Correct 22 ms 31580 KB Output is correct
26 Correct 26 ms 31596 KB Output is correct
27 Correct 25 ms 31620 KB Output is correct
28 Correct 14 ms 25180 KB Output is correct