oj.uz

답안 #399410

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
399410 2021-05-05T17:25:46 Z couplefire 캥거루 (CEOI16_kangaroo) C++17
100 / 100
 22 ms 14076 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 2000+5;
const int MOD = 1000000007;

inline int add(int a, int b){return (a+b>=MOD)?a+b-MOD:a+b;}
inline void inc(int& a, int b){a = add(a, b);}
inline int sub(int a, int b){return (a-b<0)?a-b+MOD:a-b;}
inline void dec(int &a, int b){a = sub(a, b);}
inline int mul(int a, int b){return 1ll*a*b%MOD;}
inline void grow(int &a, int b){a = mul(a, b);}

int n, cs, cf;
int dp[N][N];

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> cs >> cf;
    if(cs > cf) cs = n+1-cs, cf = n+1-cf;
    dp[0][0] = 1;
    for(int i = 1; i<cs; i++) for(int j = 1; j<=i; j++) inc(dp[i][j], add(mul(dp[i-1][j+1], j), mul(dp[i-1][j-1], j)));
    for(int j = 1; j<=cs; j++) inc(dp[cs][j], add(dp[cs-1][j], dp[cs-1][j-1]));
    for(int i = cs+1; i<cf; i++) for(int j = 1; j<=i; j++) inc(dp[i][j], add(mul(dp[i-1][j+1], j), mul(dp[i-1][j-1], j-1)));
    for(int j = 1; j<=cf; j++) inc(dp[cf][j], add(dp[cf-1][j], dp[cf-1][j-1]));
    for(int i = cf+1; i<=n; i++) for(int j = 1; j<=i; j++) inc(dp[i][j], add(mul(dp[i-1][j+1], j), mul(dp[i-1][j-1], j-2)));
    cout << dp[n][1] << endl;
}

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 464 KB Output is correct
5 Correct 1 ms 448 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct

Subtask #3
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 464 KB Output is correct
5 Correct 1 ms 448 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 2 ms 1092 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 1 ms 1100 KB Output is correct
15 Correct 1 ms 1100 KB Output is correct
16 Correct 2 ms 1100 KB Output is correct
17 Correct 2 ms 1100 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1100 KB Output is correct
20 Correct 1 ms 1100 KB Output is correct

Subtask #4
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 464 KB Output is correct
5 Correct 1 ms 448 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 2 ms 1092 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 1 ms 1100 KB Output is correct
15 Correct 1 ms 1100 KB Output is correct
16 Correct 2 ms 1100 KB Output is correct
17 Correct 2 ms 1100 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1100 KB Output is correct
20 Correct 1 ms 1100 KB Output is correct
21 Correct 4 ms 3788 KB Output is correct
22 Correct 5 ms 4044 KB Output is correct
23 Correct 5 ms 4428 KB Output is correct
24 Correct 20 ms 14076 KB Output is correct
25 Correct 22 ms 14072 KB Output is correct
26 Correct 22 ms 14012 KB Output is correct
27 Correct 20 ms 13992 KB Output is correct
28 Correct 13 ms 10188 KB Output is correct