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Submission #963017

# Submission time Handle Problem Language Result Execution time Memory
963017 2024-04-14T11:07:03 Z Ghetto Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 37 ms 31732 KB 
#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const int MAX_N = 2e3 + 5;
const lint MOD = 1e9 + 7;

int n;
int s, f;

lint mod(lint x) {
    return x % MOD;
}

lint dp[MAX_N][MAX_N];
void do_dp() {
    dp[1][1] = 1;
    for (int i = 1; i < n; i++) {
        for (int c = 1; c <= n; c++) {
            if ((i + 1) == s || (i + 1) == f) {
                dp[i + 1][c + 1] = mod(dp[i + 1][c + 1] + dp[i][c]);
                dp[i + 1][c] = mod(dp[i + 1][c] + dp[i][c]);
                continue;
            }

            lint mult = c + 1;
            mult -= (bool) (i + 1 > s);
            mult -= (bool) (i + 1 > f);
            
            dp[i + 1][c + 1] = mod(dp[i + 1][c + 1] + mod(dp[i][c] * mult));
            dp[i + 1][c - 1] = mod(dp[i + 1][c - 1] + mod(dp[i][c] * (c - 1)));
        }
    }
}

int main() {
    // freopen("kangaroo.in", "r", stdin);

    cin >> n >> s >> f;
    if (s > f) swap(s, f);

    do_dp();
    cout << dp[n][1] << '\n';

    // for (int i = 1; i <= n; i++) 
    //     for (int c = 1; c <= n; c++)
    //         cout << i << " " << c << ": " << dp[i][c] << endl;
    
}

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 0 ms 348 KB Output is correct
4 Correct 1 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 0 ms 604 KB Output is correct
10 Correct 0 ms 604 KB Output is correct
11 Correct 0 ms 604 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 0 ms 348 KB Output is correct
4 Correct 1 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 0 ms 604 KB Output is correct
10 Correct 0 ms 604 KB Output is correct
11 Correct 0 ms 604 KB Output is correct
12 Correct 1 ms 1372 KB Output is correct
13 Correct 1 ms 1380 KB Output is correct
14 Correct 1 ms 1460 KB Output is correct
15 Correct 2 ms 1372 KB Output is correct
16 Correct 1 ms 1372 KB Output is correct
17 Correct 1 ms 1368 KB Output is correct
18 Correct 1 ms 1368 KB Output is correct
19 Correct 1 ms 1368 KB Output is correct
20 Correct 1 ms 1372 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 0 ms 348 KB Output is correct
4 Correct 1 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 0 ms 604 KB Output is correct
10 Correct 0 ms 604 KB Output is correct
11 Correct 0 ms 604 KB Output is correct
12 Correct 1 ms 1372 KB Output is correct
13 Correct 1 ms 1380 KB Output is correct
14 Correct 1 ms 1460 KB Output is correct
15 Correct 2 ms 1372 KB Output is correct
16 Correct 1 ms 1372 KB Output is correct
17 Correct 1 ms 1368 KB Output is correct
18 Correct 1 ms 1368 KB Output is correct
19 Correct 1 ms 1368 KB Output is correct
20 Correct 1 ms 1372 KB Output is correct
21 Correct 5 ms 6232 KB Output is correct
22 Correct 6 ms 7004 KB Output is correct
23 Correct 6 ms 7772 KB Output is correct
24 Correct 35 ms 31668 KB Output is correct
25 Correct 36 ms 31732 KB Output is correct
26 Correct 34 ms 31576 KB Output is correct
27 Correct 37 ms 31460 KB Output is correct
28 Correct 24 ms 23896 KB Output is correct