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Submission #307739

# Submission time Handle Problem Language Result Execution time Memory
307739 2020-09-29T08:49:15 Z fishy15 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 47 ms 31736 KB 
// explanation of solution at below link
// https://codeforces.com/blog/entry/47764#comment-704139

#include <iostream>
#include <iomanip>
#include <fstream>
#include <vector>
#include <array>
#include <algorithm>
#include <utility>
#include <map>
#include <queue>
#include <set>
#include <cmath>
#include <cstdio>
#include <cstring>

#define ll long long
#define ld long double
#define eps 1e-8
#define MOD 1000000007

#define INF 0x3f3f3f3f
#define INFLL 0x3f3f3f3f3f3f3f3f

// change if necessary
#define MAXN 2010 

using namespace std;

int n, cs, cf;
ll dp[MAXN][MAXN];

int main() {
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> cs >> cf;

    dp[1][1] = 1;
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            if (i == cs || i == cf) {
                dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
                if (dp[i][j] >= MOD) dp[i][j] -= MOD;
            } else {
                dp[i][j] += (dp[i - 1][j + 1]) * j % MOD;
                dp[i][j] += (dp[i - 1][j - 1]) * (j - (i > cs) - (i > cf)) % MOD;
                if (dp[i][j] >= MOD) 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 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 512 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 512 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 2 ms 1408 KB Output is correct
13 Correct 1 ms 1408 KB Output is correct
14 Correct 2 ms 1408 KB Output is correct
15 Correct 2 ms 1408 KB Output is correct
16 Correct 1 ms 1408 KB Output is correct
17 Correct 1 ms 1408 KB Output is correct
18 Correct 2 ms 1280 KB Output is correct
19 Correct 1 ms 1408 KB Output is correct
20 Correct 2 ms 1400 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 512 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 2 ms 1408 KB Output is correct
13 Correct 1 ms 1408 KB Output is correct
14 Correct 2 ms 1408 KB Output is correct
15 Correct 2 ms 1408 KB Output is correct
16 Correct 1 ms 1408 KB Output is correct
17 Correct 1 ms 1408 KB Output is correct
18 Correct 2 ms 1280 KB Output is correct
19 Correct 1 ms 1408 KB Output is correct
20 Correct 2 ms 1400 KB Output is correct
21 Correct 7 ms 6400 KB Output is correct
22 Correct 8 ms 6912 KB Output is correct
23 Correct 9 ms 7800 KB Output is correct
24 Correct 44 ms 31736 KB Output is correct
25 Correct 47 ms 31736 KB Output is correct
26 Correct 44 ms 31736 KB Output is correct
27 Correct 44 ms 31608 KB Output is correct
28 Correct 29 ms 23928 KB Output is correct