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답안 #307386

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
307386 2020-09-28T03:50:00 Z jungsnow 캥거루 (CEOI16_kangaroo) C++14
100 / 100
 300 ms 70776 KB 
#include<bits/stdc++.h>
#define int long long
#define bug(x) cerr<<#x<<" = "<<x<<'\n'

using namespace std;

const int mod = 1e9 + 7;
const int N = 2001;

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

void mul(int& a, int b) {
    a = 1ll * a * b % mod;
}

int st, en, n;
int dp[N][N][4];
/// 0 - 00; 1 - 10, 2 - 01, 3 - 11;

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
//    freopen("kangaroo.in", "r", stdin);
//    freopen("kangaroo.out", "w", stdout);
    cin>>n>>st>>en;
    dp[0][2][0] = 1;
    int cur = 0;
    if (st > en) swap(st, en);
    for (int i = 0; i < n - 2; ++i) {
        ++cur;
        if (cur == st) ++cur;
        if (cur == en) ++cur;
        for (int j = 1; j <= i + 2; ++j) {
            for (int k = 0; k < 4; ++k) {
                if (dp[i][j][k] == 0) continue;
                if (i == n - 3 && j == 2 && k == 3)
                    add(dp[n - 2][1][k], dp[i][j][k]);

                for (int t = 0; t < 2; ++t) if ((k >> t & 1) == 0){
                    int m = (t == 0 ? st : en), d = __builtin_popcount(k);
                    if (i < n - 3) {
                        if (cur > m && j > 2)
                            add(dp[i + 1][j - 1][k | (1 << t)], 1ll * dp[i][j][k] * (j - 2) % mod);
                        else if (cur < m)
                            add(dp[i + 1][j][k | (1 << t)], dp[i][j][k]);
                    } else if (j == 2 && cur > m && d == 1) {
                            add(dp[i + 1][1][3], dp[i][j][k]);
                    }
                } else if (i < n - 3) {
                    add(dp[i + 1][j - 1][k], 1ll * dp[i][j][k] * (j - 2) % mod);
                }
                add(dp[i + 1][j + 1][k], dp[i][j][k]);
                if (j > 3) add(dp[i + 1][j - 1][k], 1ll * (dp[i][j][k] * (j - 2)) % mod * (j - 3) % mod);
            }
        }
    }
    cout << dp[n - 2][1][3];
}

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct

Subtask #3
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 4 ms 1792 KB Output is correct
13 Correct 4 ms 1664 KB Output is correct
14 Correct 3 ms 1824 KB Output is correct
15 Correct 4 ms 1792 KB Output is correct
16 Correct 4 ms 1920 KB Output is correct
17 Correct 4 ms 1792 KB Output is correct
18 Correct 3 ms 1568 KB Output is correct
19 Correct 4 ms 1792 KB Output is correct
20 Correct 4 ms 1792 KB Output is correct

Subtask #4
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 4 ms 1792 KB Output is correct
13 Correct 4 ms 1664 KB Output is correct
14 Correct 3 ms 1824 KB Output is correct
15 Correct 4 ms 1792 KB Output is correct
16 Correct 4 ms 1920 KB Output is correct
17 Correct 4 ms 1792 KB Output is correct
18 Correct 3 ms 1568 KB Output is correct
19 Correct 4 ms 1792 KB Output is correct
20 Correct 4 ms 1792 KB Output is correct
21 Correct 34 ms 9752 KB Output is correct
22 Correct 37 ms 10872 KB Output is correct
23 Correct 44 ms 12280 KB Output is correct
24 Correct 278 ms 70688 KB Output is correct
25 Correct 255 ms 70776 KB Output is correct
26 Correct 279 ms 70776 KB Output is correct
27 Correct 300 ms 70264 KB Output is correct
28 Correct 165 ms 41464 KB Output is correct