Submission #528333

# Submission time Handle Problem Language Result Execution time Memory
528333 2022-02-20T03:42:08 Z KoD Kangaroo (CEOI16_kangaroo) C++17
100 / 100
68 ms 756 KB
#include <bits/stdc++.h>

using std::vector;
using std::array;
using std::pair;
using std::tuple;

using ll = long long;

constexpr int MOD = 1000000007;

struct Fp {
    int x;
    Fp(const int x = 0) : x(x) {}
    Fp& operator+=(const Fp& t) {
        if ((x += t.x) >= MOD) x -= MOD;
        return *this;
    }
    Fp operator+(const Fp& t) const {
        return Fp(*this) += t;
    }
    Fp operator*(const Fp& t) const {
        return Fp((ll)x * t.x % MOD);
    }
};

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int N, src, dst;
    std::cin >> N >> src >> dst;
    vector<array<array<Fp, 2>, 2>> dp(1);
    dp[0][1][0] = 1;
    for (int cell = 2; cell <= N; ++cell) {
        const int n = dp.size();
        vector<array<array<Fp, 2>, 2>> next(n + 1);
        if (cell != dst and cell <= src) {
            for (int i = 0; i < n; ++i) for (int j : {0, 1}) for (int k : {0, 1}) {
                if (j == 1) next[i + 1][1][k] += dp[i][j][k];
                if (j == 1) next[i][0][k] += dp[i][j][k];
            }
        }
        if (cell != src and cell <= dst) {
            for (int i = 0; i < n; ++i) for (int j : {0, 1}) for (int k : {0, 1}) {
                if (k == 0) next[i + 1][j][0] += dp[i][j][k];
                if (k == 0) next[i][j][1] += dp[i][j][k];
            }
        }
        if (cell != src and cell != dst) {
            for (int i = 0; i < n; ++i) for (int j : {0, 1}) for (int k : {0, 1}) {
                next[i + 1][j][k] += dp[i][j][k] * i;
                if (i > 0) next[i - 1][j][k] += dp[i][j][k] * i;
            }
        }
        dp = std::move(next);
    }
    Fp ans = 0;
    for (int j : {0, 1}) for (int k : {0, 1}) {
        ans += dp[0][j][k];
    }
    std::cout << ans.x << '\n';
    return 0;
}
# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 312 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 0 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 312 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 0 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
12 Correct 1 ms 312 KB Output is correct
13 Correct 1 ms 308 KB Output is correct
14 Correct 2 ms 332 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 1 ms 332 KB Output is correct
17 Correct 2 ms 332 KB Output is correct
18 Correct 2 ms 332 KB Output is correct
19 Correct 1 ms 332 KB Output is correct
20 Correct 1 ms 332 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 312 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 0 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
12 Correct 1 ms 312 KB Output is correct
13 Correct 1 ms 308 KB Output is correct
14 Correct 2 ms 332 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 1 ms 332 KB Output is correct
17 Correct 2 ms 332 KB Output is correct
18 Correct 2 ms 332 KB Output is correct
19 Correct 1 ms 332 KB Output is correct
20 Correct 1 ms 332 KB Output is correct
21 Correct 7 ms 332 KB Output is correct
22 Correct 8 ms 332 KB Output is correct
23 Correct 9 ms 332 KB Output is correct
24 Correct 64 ms 376 KB Output is correct
25 Correct 61 ms 376 KB Output is correct
26 Correct 68 ms 756 KB Output is correct
27 Correct 55 ms 416 KB Output is correct
28 Correct 32 ms 304 KB Output is correct