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Submission #305960

# Submission time Handle Problem Language Result Execution time Memory
305960 2020-09-24T07:36:25 Z two_sides Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 17 ms 14208 KB 
#include <bits/stdc++.h>
using namespace std;

using ll = long long;

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

int dp[N][N];

int madd(int x, int y) {
    if ((x += y) >= MOD)
        x -= MOD;
    return x;
}

int mmul(int x, int y) {
    return ll(x) * y % MOD;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n, s, t; cin >> n >> s >> t;
    dp[1][1] = 1;
    for (int i = 2; i <= n; i++)
        for (int j = 1; j <= i; j++) {
            if (i == s || i == t)
                dp[i][j] = madd(dp[i - 1][j - 1], dp[i - 1][j]);
            else dp[i][j] = madd(mmul(dp[i - 1][j + 1], j),
            mmul(dp[i - 1][j - 1], j - (i > s) - (i > t)));
        }
    cout << dp[n][1] << '\n';
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 1152 KB Output is correct
13 Correct 2 ms 1184 KB Output is correct
14 Correct 1 ms 1152 KB Output is correct
15 Correct 1 ms 1152 KB Output is correct
16 Correct 1 ms 1152 KB Output is correct
17 Correct 1 ms 1152 KB Output is correct
18 Correct 1 ms 1152 KB Output is correct
19 Correct 1 ms 1152 KB Output is correct
20 Correct 1 ms 1152 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 1152 KB Output is correct
13 Correct 2 ms 1184 KB Output is correct
14 Correct 1 ms 1152 KB Output is correct
15 Correct 1 ms 1152 KB Output is correct
16 Correct 1 ms 1152 KB Output is correct
17 Correct 1 ms 1152 KB Output is correct
18 Correct 1 ms 1152 KB Output is correct
19 Correct 1 ms 1152 KB Output is correct
20 Correct 1 ms 1152 KB Output is correct
21 Correct 3 ms 3840 KB Output is correct
22 Correct 4 ms 4096 KB Output is correct
23 Correct 4 ms 4480 KB Output is correct
24 Correct 17 ms 14208 KB Output is correct
25 Correct 17 ms 14080 KB Output is correct
26 Correct 17 ms 14208 KB Output is correct
27 Correct 17 ms 14080 KB Output is correct
28 Correct 12 ms 10240 KB Output is correct