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Submission #393923

# Submission time Handle Problem Language Result Execution time Memory
393923 2021-04-24T22:44:25 Z KhaledFarhat Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 29 ms 16072 KB 
#include <bits/stdc++.h>
using namespace std;

const int MOD = 1000000007;

int Add(int x, int y) {
    return (x + y) % MOD;
}

void Increase(int& x, int y) {
    x = Add(x, y);
}

int Multiply(int x, int y) {
    return 1LL * x * y % MOD;
}

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

    int n, startPosition, finishPosition;
    cin >> n >> startPosition >> finishPosition;

    vector<vector<int>> ways(n + 2, vector<int>(n + 1));

    ways[2][1] = 1;

    for (int i = 2; i <= n; ++i) {
        for (int components = 1; components < i; ++components) {
            if (ways[i][components] == 0) {
                continue;
            }

            if (i == startPosition || i == finishPosition) {
                Increase(ways[i + 1][components + 1], ways[i][components]); // open a new component on the side
                Increase(ways[i + 1][components], ways[i][components]); // append to the side
            }
            else {
                // create a new component
                int validPosition = (components + 1) - (i > startPosition) - (i > finishPosition);
                Increase(ways[i + 1][components + 1], Multiply(validPosition, ways[i][components]));

                // merge two component
                validPosition = components - 1;
                Increase(ways[i + 1][components - 1], Multiply(validPosition, ways[i][components]));
            }
        }
    }

    cout << ways[n + 1][1];

    return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 316 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 1 ms 204 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 316 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 1 ms 204 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct
12 Correct 1 ms 444 KB Output is correct
13 Correct 1 ms 444 KB Output is correct
14 Correct 1 ms 460 KB Output is correct
15 Correct 1 ms 460 KB Output is correct
16 Correct 1 ms 460 KB Output is correct
17 Correct 1 ms 460 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 1 ms 460 KB Output is correct
20 Correct 1 ms 460 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 316 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 1 ms 204 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct
12 Correct 1 ms 444 KB Output is correct
13 Correct 1 ms 444 KB Output is correct
14 Correct 1 ms 460 KB Output is correct
15 Correct 1 ms 460 KB Output is correct
16 Correct 1 ms 460 KB Output is correct
17 Correct 1 ms 460 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 1 ms 460 KB Output is correct
20 Correct 1 ms 460 KB Output is correct
21 Correct 3 ms 1980 KB Output is correct
22 Correct 4 ms 2252 KB Output is correct
23 Correct 5 ms 2500 KB Output is correct
24 Correct 29 ms 16064 KB Output is correct
25 Correct 26 ms 16072 KB Output is correct
26 Correct 28 ms 15948 KB Output is correct
27 Correct 28 ms 15936 KB Output is correct
28 Correct 17 ms 9184 KB Output is correct