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Submission #558092

# Submission time Handle Problem Language Result Execution time Memory
558092 2022-05-06T19:27:16 Z Alexandruabcde Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 35 ms 15948 KB 
#include <bits/stdc++.h>

using namespace std;

constexpr int NMAX = 2005;
constexpr int MOD = 1e9 + 7;

int N, cs, cf;
int dp[NMAX][NMAX];

void Add (int &x, int y) {
    x = x + y;
    if (x >= MOD) x -= MOD;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> cs >> cf;

    dp[1][1] = 1;

    for (int i = 1; i < N; ++ i ) {
        for (int j = 1; j <= N; ++ j ) {
            if (i + 1 == cs || i + 1 == cf) {
                Add(dp[i+1][j], dp[i][j]);
                Add(dp[i+1][j+1], dp[i][j]);
            }
            else {
                Add(dp[i+1][j-1], 1LL * (j-1) * dp[i][j] % MOD);
                Add(dp[i+1][j+1], 1LL * (j+1 - (i >= cs) - (i >= cf)) * dp[i][j] % MOD);
            }
        }
    }

    cout << dp[N][1] << '\n';

    return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 2 ms 1228 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 2 ms 1236 KB Output is correct
15 Correct 1 ms 1264 KB Output is correct
16 Correct 1 ms 1224 KB Output is correct
17 Correct 1 ms 1236 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1236 KB Output is correct
20 Correct 2 ms 1228 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 2 ms 1228 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 2 ms 1236 KB Output is correct
15 Correct 1 ms 1264 KB Output is correct
16 Correct 1 ms 1224 KB Output is correct
17 Correct 1 ms 1236 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1236 KB Output is correct
20 Correct 2 ms 1228 KB Output is correct
21 Correct 6 ms 4556 KB Output is correct
22 Correct 6 ms 4948 KB Output is correct
23 Correct 7 ms 5460 KB Output is correct
24 Correct 35 ms 15896 KB Output is correct
25 Correct 34 ms 15948 KB Output is correct
26 Correct 34 ms 15900 KB Output is correct
27 Correct 34 ms 15904 KB Output is correct
28 Correct 20 ms 12024 KB Output is correct