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Submission #24974

# Submission time Handle Problem Language Result Execution time Memory
24974 2017-06-19T13:09:53 Z kajebiii Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 46 ms 17800 KB 
#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define REPO(i,n) for(int (i)=1; (i)<=(int)(n); (i)++)
#define SZ(v) ((int)(v).size())
#define ALL(v) (v).begin(),(v).end()
#define one first
#define two second
typedef long long ll;
typedef pair<int, int> pi;
const int INF = 0x3f2f1f0f;
const ll LINF = 1ll * INF * INF;

const int MOD = 1e9 + 7, MAX_N = 2e3 + 10;

int N, S, E, Dy[MAX_N][MAX_N];
void add(int &a, int b) {
	if((a+=b) >= MOD) a -= MOD;
	if(a < 0) a += MOD;
}
int main() {
	cin >> N >> S >> E;

	Dy[0][0] = 1;
	int cnt = 0;
	for(int i=1; i<=N; i++) {
		if(i == S || i == E) {
			for(int j=0; j<=N; j++) {
				add(Dy[i][j], Dy[i-1][j]);
				add(Dy[i][j], Dy[i-1][j-1]);
			}
			cnt++;
		} else {
			for(int j=0; j<=N; j++) {
				if(j) add(Dy[i][j], 1ll * Dy[i-1][j-1] * (j - cnt) % MOD);
				add(Dy[i][j], 1ll * Dy[i-1][j+1] * j % MOD);
			}
		}
	}
	printf("%d\n", Dy[N][1]);
	return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17800 KB Output is correct
2 Correct 0 ms 17800 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17800 KB Output is correct
2 Correct 0 ms 17800 KB Output is correct
3 Correct 0 ms 17800 KB Output is correct
4 Correct 0 ms 17800 KB Output is correct
5 Correct 0 ms 17800 KB Output is correct
6 Correct 0 ms 17800 KB Output is correct
7 Correct 0 ms 17800 KB Output is correct
8 Correct 0 ms 17800 KB Output is correct
9 Correct 0 ms 17800 KB Output is correct
10 Correct 0 ms 17800 KB Output is correct
11 Correct 0 ms 17800 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17800 KB Output is correct
2 Correct 0 ms 17800 KB Output is correct
3 Correct 0 ms 17800 KB Output is correct
4 Correct 0 ms 17800 KB Output is correct
5 Correct 0 ms 17800 KB Output is correct
6 Correct 0 ms 17800 KB Output is correct
7 Correct 0 ms 17800 KB Output is correct
8 Correct 0 ms 17800 KB Output is correct
9 Correct 0 ms 17800 KB Output is correct
10 Correct 0 ms 17800 KB Output is correct
11 Correct 0 ms 17800 KB Output is correct
12 Correct 0 ms 17800 KB Output is correct
13 Correct 0 ms 17800 KB Output is correct
14 Correct 0 ms 17800 KB Output is correct
15 Correct 0 ms 17800 KB Output is correct
16 Correct 0 ms 17800 KB Output is correct
17 Correct 0 ms 17800 KB Output is correct
18 Correct 0 ms 17800 KB Output is correct
19 Correct 0 ms 17800 KB Output is correct
20 Correct 0 ms 17800 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17800 KB Output is correct
2 Correct 0 ms 17800 KB Output is correct
3 Correct 0 ms 17800 KB Output is correct
4 Correct 0 ms 17800 KB Output is correct
5 Correct 0 ms 17800 KB Output is correct
6 Correct 0 ms 17800 KB Output is correct
7 Correct 0 ms 17800 KB Output is correct
8 Correct 0 ms 17800 KB Output is correct
9 Correct 0 ms 17800 KB Output is correct
10 Correct 0 ms 17800 KB Output is correct
11 Correct 0 ms 17800 KB Output is correct
12 Correct 0 ms 17800 KB Output is correct
13 Correct 0 ms 17800 KB Output is correct
14 Correct 0 ms 17800 KB Output is correct
15 Correct 0 ms 17800 KB Output is correct
16 Correct 0 ms 17800 KB Output is correct
17 Correct 0 ms 17800 KB Output is correct
18 Correct 0 ms 17800 KB Output is correct
19 Correct 0 ms 17800 KB Output is correct
20 Correct 0 ms 17800 KB Output is correct
21 Correct 3 ms 17800 KB Output is correct
22 Correct 3 ms 17800 KB Output is correct
23 Correct 9 ms 17800 KB Output is correct
24 Correct 46 ms 17800 KB Output is correct
25 Correct 39 ms 17800 KB Output is correct
26 Correct 39 ms 17800 KB Output is correct
27 Correct 43 ms 17800 KB Output is correct
28 Correct 26 ms 17800 KB Output is correct