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답안 #110848

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
110848 2019-05-12T13:14:22 Z mosesmayer 캥거루 (CEOI16_kangaroo) C++17
100 / 100
 82 ms 31992 KB 
#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
typedef long long LL;

const LL mod = 1e9 + 7;
int n, s, t;

LL dp[2005][2005];

LL f(int pos, int cc){
	if (pos > n) return cc == 1; // base case, reached if cc = 1 when we reach end position
	if (pos > 1 && cc < 1) return 0; // once pos after 1, impossible as we have at least 1 contiguous component
	LL &ret = dp[pos][cc];
	if (ret != -1) return ret;
	ret = 0;
	//special case --> endpoints
	if (!(pos ^ s) || !(pos ^ t)){ // UwU ಠ_ಠ
		(ret += f(pos + 1, cc)) %= mod; // already ada.
		(ret += f(pos + 1, cc + 1)) %= mod; // desired endpoint not used
	} else {
		int ends = 2 - (pos > s) - (pos > t);
		//new component --> two adjacent will be smaller
		(ret += f(pos + 1, cc + 1) * (cc - 1 + ends)) %= mod; // create new component, ends == extra empty spaces due to ends
		//merge component --> larger than two adjacent
		(ret += f(pos + 1, cc - 1) * (cc - 1)) %= mod;
	}
	return ret;
}

int main(){
	cin >> n >> s >> t;
	memset(dp, -1, sizeof(dp));
	cout << f(1, 0) << '\n';
	return 0;
}

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 31736 KB Output is correct
2 Correct 30 ms 31736 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 31736 KB Output is correct
2 Correct 30 ms 31736 KB Output is correct
3 Correct 30 ms 31948 KB Output is correct
4 Correct 27 ms 31720 KB Output is correct
5 Correct 30 ms 31736 KB Output is correct
6 Correct 27 ms 31744 KB Output is correct
7 Correct 27 ms 31736 KB Output is correct
8 Correct 29 ms 31736 KB Output is correct
9 Correct 30 ms 31744 KB Output is correct
10 Correct 31 ms 31864 KB Output is correct
11 Correct 27 ms 31744 KB Output is correct

Subtask #3
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 31736 KB Output is correct
2 Correct 30 ms 31736 KB Output is correct
3 Correct 30 ms 31948 KB Output is correct
4 Correct 27 ms 31720 KB Output is correct
5 Correct 30 ms 31736 KB Output is correct
6 Correct 27 ms 31744 KB Output is correct
7 Correct 27 ms 31736 KB Output is correct
8 Correct 29 ms 31736 KB Output is correct
9 Correct 30 ms 31744 KB Output is correct
10 Correct 31 ms 31864 KB Output is correct
11 Correct 27 ms 31744 KB Output is correct
12 Correct 25 ms 31744 KB Output is correct
13 Correct 29 ms 31736 KB Output is correct
14 Correct 28 ms 31872 KB Output is correct
15 Correct 26 ms 31736 KB Output is correct
16 Correct 25 ms 31872 KB Output is correct
17 Correct 29 ms 31864 KB Output is correct
18 Correct 27 ms 31744 KB Output is correct
19 Correct 30 ms 31844 KB Output is correct
20 Correct 28 ms 31736 KB Output is correct

Subtask #4
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 31736 KB Output is correct
2 Correct 30 ms 31736 KB Output is correct
3 Correct 30 ms 31948 KB Output is correct
4 Correct 27 ms 31720 KB Output is correct
5 Correct 30 ms 31736 KB Output is correct
6 Correct 27 ms 31744 KB Output is correct
7 Correct 27 ms 31736 KB Output is correct
8 Correct 29 ms 31736 KB Output is correct
9 Correct 30 ms 31744 KB Output is correct
10 Correct 31 ms 31864 KB Output is correct
11 Correct 27 ms 31744 KB Output is correct
12 Correct 25 ms 31744 KB Output is correct
13 Correct 29 ms 31736 KB Output is correct
14 Correct 28 ms 31872 KB Output is correct
15 Correct 26 ms 31736 KB Output is correct
16 Correct 25 ms 31872 KB Output is correct
17 Correct 29 ms 31864 KB Output is correct
18 Correct 27 ms 31744 KB Output is correct
19 Correct 30 ms 31844 KB Output is correct
20 Correct 28 ms 31736 KB Output is correct
21 Correct 33 ms 31872 KB Output is correct
22 Correct 36 ms 31780 KB Output is correct
23 Correct 34 ms 31744 KB Output is correct
24 Correct 82 ms 31872 KB Output is correct
25 Correct 80 ms 31916 KB Output is correct
26 Correct 74 ms 31872 KB Output is correct
27 Correct 79 ms 31992 KB Output is correct
28 Correct 53 ms 31872 KB Output is correct