oj.uz

Submission #35809

# Submission time Handle Problem Language Result Execution time Memory
35809 2017-11-30T18:55:50 Z DoanPhuDuc Kangaroo (CEOI16_kangaroo) C++
100 / 100
 136 ms 65204 KB 
#include <bits/stdc++.h>

#define FOR(x, a, b) for (int x = a; x <= b; ++x)
#define FOD(x, a, b) for (int x = a; x >= b; --x)
#define REP(x, a, b) for (int x = a; x < b; ++x)
#define DEBUG(X) { cout << #X << " = " << X << endl; }
#define PR(A, n) { cout << #A << " = "; FOR(_, 1, n) cout << A[_] << " "; cout << endl; }
#define PR0(A, n)  { cout << #A << " = "; REP(_, 0, n) cout << A[_] << " "; cout << endl; }

using namespace std;

typedef long long LL;

const int N = 2e3 + 10;
const int BASE = 1e9 + 7;

int n, s, t;
int dp[N][N][2][2];

void Update(int &a, int b) {
    a += b; if (a >= BASE) a -= BASE;
}

LL P2(LL n) {
    return n * (n - 1) % BASE;
}

int Compute(int i, int j, int L, int R) {
    if (j < 0) return 0;
    if (i == n) return (j == 0) ? 1 : 0;
    int &ans = dp[i][j][L][R];
    if (ans != -1) return ans;
    ans = 0;
    if (i == s) {
        Update(ans, Compute(i + 1, j, 1, R));
        Update(ans, (LL)j * Compute(i + 1, j - 1, 1, R) % BASE);
    } else if (i == t) {
        Update(ans, Compute(i + 1, j, L, 1));
        Update(ans, (LL)j * Compute(i + 1, j - 1, L, 1) % BASE);
    } else {
        Update(ans, Compute(i + 1, j + 1, L, R));
        if (L == 1) Update(ans, (LL)j * Compute(i + 1, j - 1, L, R) % BASE);
        if (R == 1) Update(ans, (LL)j * Compute(i + 1, j - 1, L, R) % BASE);
        Update(ans, P2(j) * Compute(i + 1, j - 1, L, R) % BASE);
    }
    return ans;
}

int main() {
    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif // LOCAL
    scanf("%d%d%d", &n, &s, &t);
    memset(dp, -1, sizeof dp);
    printf("%d", Compute(1, 0, 0, 0));
    return 0;
}

Compilation message

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:54:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d", &n, &s, &t);
                                ^

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 65140 KB Output is correct
2 Correct 9 ms 65140 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 65140 KB Output is correct
2 Correct 9 ms 65140 KB Output is correct
3 Correct 3 ms 65140 KB Output is correct
4 Correct 6 ms 65140 KB Output is correct
5 Correct 3 ms 65140 KB Output is correct
6 Correct 6 ms 65140 KB Output is correct
7 Correct 0 ms 65140 KB Output is correct
8 Correct 6 ms 65140 KB Output is correct
9 Correct 13 ms 65140 KB Output is correct
10 Correct 3 ms 65140 KB Output is correct
11 Correct 9 ms 65140 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 65140 KB Output is correct
2 Correct 9 ms 65140 KB Output is correct
3 Correct 3 ms 65140 KB Output is correct
4 Correct 6 ms 65140 KB Output is correct
5 Correct 3 ms 65140 KB Output is correct
6 Correct 6 ms 65140 KB Output is correct
7 Correct 0 ms 65140 KB Output is correct
8 Correct 6 ms 65140 KB Output is correct
9 Correct 13 ms 65140 KB Output is correct
10 Correct 3 ms 65140 KB Output is correct
11 Correct 9 ms 65140 KB Output is correct
12 Correct 6 ms 65140 KB Output is correct
13 Correct 9 ms 65140 KB Output is correct
14 Correct 0 ms 65140 KB Output is correct
15 Correct 9 ms 65140 KB Output is correct
16 Correct 0 ms 65140 KB Output is correct
17 Correct 6 ms 65140 KB Output is correct
18 Correct 3 ms 65140 KB Output is correct
19 Correct 9 ms 65140 KB Output is correct
20 Correct 9 ms 65140 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 65140 KB Output is correct
2 Correct 9 ms 65140 KB Output is correct
3 Correct 3 ms 65140 KB Output is correct
4 Correct 6 ms 65140 KB Output is correct
5 Correct 3 ms 65140 KB Output is correct
6 Correct 6 ms 65140 KB Output is correct
7 Correct 0 ms 65140 KB Output is correct
8 Correct 6 ms 65140 KB Output is correct
9 Correct 13 ms 65140 KB Output is correct
10 Correct 3 ms 65140 KB Output is correct
11 Correct 9 ms 65140 KB Output is correct
12 Correct 6 ms 65140 KB Output is correct
13 Correct 9 ms 65140 KB Output is correct
14 Correct 0 ms 65140 KB Output is correct
15 Correct 9 ms 65140 KB Output is correct
16 Correct 0 ms 65140 KB Output is correct
17 Correct 6 ms 65140 KB Output is correct
18 Correct 3 ms 65140 KB Output is correct
19 Correct 9 ms 65140 KB Output is correct
20 Correct 9 ms 65140 KB Output is correct
21 Correct 13 ms 65140 KB Output is correct
22 Correct 19 ms 65140 KB Output is correct
23 Correct 16 ms 65140 KB Output is correct
24 Correct 116 ms 65200 KB Output is correct
25 Correct 136 ms 65204 KB Output is correct
26 Correct 126 ms 65200 KB Output is correct
27 Correct 126 ms 65196 KB Output is correct
28 Correct 66 ms 65152 KB Output is correct