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Submission #972765

# Submission time Handle Problem Language Result Execution time Memory
972765 2024-05-01T06:51:58 Z Beerus13 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 12 ms 14192 KB 
#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 2e3 + 5;
const int mod = 1e9 + 7;

void add(int &a, int b) {
    a += b;
    if(a >= mod) a -= mod;
    if(a < 0) a += mod;
}

int n, sta, fin;
int dp[N][N];

void solve() {
    cin >> n >> sta >> fin;
    dp[0][0] = 1;
    for(int i = 1; i <= n; ++i) {
        for(int j = 1; j <= i; ++j) {
            if(i == sta || i == fin) {
                add(dp[i][j], (dp[i - 1][j - 1] + dp[i - 1][j]) % mod);
            }
            else {
                int res = j - (i > sta) - (i > fin);
                add(dp[i][j], (1ll * dp[i - 1][j - 1] * res + 1ll * j * dp[i - 1][j + 1]) % mod);
            }
        }
    }
    cout << dp[n][1] << '\n';
}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int test = 1;
    // cin >> test;
    while(test--) solve();
    return 0;
}

// https://oj.uz/problem/view/CEOI16_kangaroo

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 0 ms 344 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 604 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 0 ms 604 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 0 ms 604 KB Output is correct
9 Correct 1 ms 600 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 1 ms 460 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 604 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 0 ms 604 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 0 ms 604 KB Output is correct
9 Correct 1 ms 600 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 1116 KB Output is correct
13 Correct 1 ms 1112 KB Output is correct
14 Correct 1 ms 1116 KB Output is correct
15 Correct 1 ms 1116 KB Output is correct
16 Correct 1 ms 1372 KB Output is correct
17 Correct 1 ms 1116 KB Output is correct
18 Correct 1 ms 1228 KB Output is correct
19 Correct 1 ms 1116 KB Output is correct
20 Correct 1 ms 1116 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 604 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 0 ms 604 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 0 ms 604 KB Output is correct
9 Correct 1 ms 600 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 1116 KB Output is correct
13 Correct 1 ms 1112 KB Output is correct
14 Correct 1 ms 1116 KB Output is correct
15 Correct 1 ms 1116 KB Output is correct
16 Correct 1 ms 1372 KB Output is correct
17 Correct 1 ms 1116 KB Output is correct
18 Correct 1 ms 1228 KB Output is correct
19 Correct 1 ms 1116 KB Output is correct
20 Correct 1 ms 1116 KB Output is correct
21 Correct 2 ms 3932 KB Output is correct
22 Correct 2 ms 4188 KB Output is correct
23 Correct 3 ms 4444 KB Output is correct
24 Correct 11 ms 14172 KB Output is correct
25 Correct 12 ms 14168 KB Output is correct
26 Correct 11 ms 14192 KB Output is correct
27 Correct 12 ms 14172 KB Output is correct
28 Correct 7 ms 10332 KB Output is correct