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Submission #514864

# Submission time Handle Problem Language Result Execution time Memory
514864 2022-01-18T16:30:58 Z losmi247 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 34 ms 22980 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2005;
const int mod = 1000000007;

ll n,s,e;
ll dp[N][N];

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    /*freopen("kangaroo.in","r",stdin);
    freopen("kangaroo.out","w",stdout);*/

    cin >> n >> s >> e;

    dp[0][0] = 1;
    for(int i = 1; i <= n; i++){
        for(ll j = 1; j <= i; j++){
            if(i == s){
                /// create a new component at the beginning or just put it at the beginning
                dp[i][j] += dp[i-1][j-1]+dp[i-1][j];
                dp[i][j] %= mod;
                continue;
            }
            if(i == e){
                /// create a new component at the end or just put it at the end
                dp[i][j] += dp[i-1][j-1]+dp[i-1][j];
                dp[i][j] %= mod;
                continue;
            }

            /// create a new component
            dp[i][j] += (dp[i-1][j-1]*(j-(i > s)-(i > e)))%mod;
            dp[i][j] %= mod;
            /// we can't put new elements at the ends or the beginnings of existing components
            /// merge two components - always valid
            dp[i][j] += (dp[i-1][j+1]*j)%mod;
            dp[i][j] %= mod;
        }
    }

    cout << dp[n][1] << endl;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 316 KB Output is correct
2 Correct 0 ms 324 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 316 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 452 KB Output is correct
5 Correct 1 ms 452 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 452 KB Output is correct
8 Correct 1 ms 452 KB Output is correct
9 Correct 0 ms 460 KB Output is correct
10 Correct 1 ms 448 KB Output is correct
11 Correct 1 ms 460 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 316 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 452 KB Output is correct
5 Correct 1 ms 452 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 452 KB Output is correct
8 Correct 1 ms 452 KB Output is correct
9 Correct 0 ms 460 KB Output is correct
10 Correct 1 ms 448 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1200 KB Output is correct
14 Correct 1 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1228 KB Output is correct
17 Correct 1 ms 1228 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1228 KB Output is correct
20 Correct 2 ms 1216 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 316 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 452 KB Output is correct
5 Correct 1 ms 452 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 452 KB Output is correct
8 Correct 1 ms 452 KB Output is correct
9 Correct 0 ms 460 KB Output is correct
10 Correct 1 ms 448 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1200 KB Output is correct
14 Correct 1 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1228 KB Output is correct
17 Correct 1 ms 1228 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1228 KB Output is correct
20 Correct 2 ms 1216 KB Output is correct
21 Correct 5 ms 4556 KB Output is correct
22 Correct 5 ms 4928 KB Output is correct
23 Correct 6 ms 5500 KB Output is correct
24 Correct 34 ms 22944 KB Output is correct
25 Correct 27 ms 22888 KB Output is correct
26 Correct 26 ms 22980 KB Output is correct
27 Correct 25 ms 22840 KB Output is correct
28 Correct 16 ms 15036 KB Output is correct