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Submission #559928

# Submission time Handle Problem Language Result Execution time Memory
559928 2022-05-11T01:11:02 Z hoanghq2004 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 25 ms 14128 KB 
#include <bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 7;
const int Nmax = 2010;

int n;
int S, T;
int f[Nmax][Nmax];

int main() {
    cin >> n >> S >> T;
    f[1][1] = 1;
    for (int i = 1; i < n; ++i) {
        for (int j = 1; j <= i; ++j) {
            if (f[i][j] == 0) continue;
            if (i + 1 == S || i + 1 == T) {
                f[i + 1][j] += f[i][j];
                f[i + 1][j + 1] += f[i][j];
                if (f[i + 1][j] >= mod) f[i + 1][j] -= mod;
                if (f[i + 1][j + 1] >= mod) f[i + 1][j + 1] -= mod;
            } else {
                f[i + 1][j - 1] += 1LL * f[i][j] * (j - 1) % mod;
                if (f[i + 1][j - 1] >= mod) f[i + 1][j - 1] -= mod;
                f[i + 1][j + 1] += 1LL * (j + 1 - (i + 1 > S) - (i + 1 > T)) * f[i][j] % mod;
                if (f[i + 1][j + 1] >= mod) f[i + 1][j + 1] -= mod;
            }
        }
    }
    cout << f[n][1];
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 312 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 312 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 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 436 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 0 ms 212 KB Output is correct
2 Correct 1 ms 312 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 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 436 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 1108 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 1 ms 1108 KB Output is correct
15 Correct 1 ms 1108 KB Output is correct
16 Correct 1 ms 1108 KB Output is correct
17 Correct 1 ms 1108 KB Output is correct
18 Correct 1 ms 980 KB Output is correct
19 Correct 1 ms 1080 KB Output is correct
20 Correct 1 ms 1108 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 312 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 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 436 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 1108 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 1 ms 1108 KB Output is correct
15 Correct 1 ms 1108 KB Output is correct
16 Correct 1 ms 1108 KB Output is correct
17 Correct 1 ms 1108 KB Output is correct
18 Correct 1 ms 980 KB Output is correct
19 Correct 1 ms 1080 KB Output is correct
20 Correct 1 ms 1108 KB Output is correct
21 Correct 3 ms 3772 KB Output is correct
22 Correct 4 ms 4052 KB Output is correct
23 Correct 5 ms 4436 KB Output is correct
24 Correct 18 ms 14028 KB Output is correct
25 Correct 19 ms 14040 KB Output is correct
26 Correct 25 ms 14128 KB Output is correct
27 Correct 21 ms 13988 KB Output is correct
28 Correct 12 ms 10180 KB Output is correct