Submission #3402085


Source Code Expand

#include <iostream>
#include <vector>
#define llint long long
#define mod 1000000007

using namespace std;

struct SegTree{
	int size;
	vector<llint> seg;
	
	SegTree(){}
	SegTree(int size){
		this->size = size;
		seg.resize(1<<(size+1));
	}
	
	void init()
	{
		for(int i = 0; i < (1<<(size+1)); i++) seg[i] = 0;
	}
	
	void update(int i, llint val)
	{
		i += (1 << size);
		seg[i] = val;
		while(i > 1){
			i /= 2;
			seg[i] = (seg[i*2]+seg[i*2+1]) % mod;
		}
	}

	llint query(int a, int b, int k, int l, int r)
	{
		if(b < l || r < a) return 0;
		if(a <= l && r <= b) return seg[k];
		llint lval = query(a, b, k*2, l, (l+r)/2);
		llint rval = query(a, b, k*2+1, (l+r)/2+1, r);
		return (lval+rval)%mod;
	}
	llint query(int a, int b)
	{
		if(a > b) return 0;
		return query(a, b, 1, 0, (1<<size)-1);
	}
};

llint fact[100005], fact_inv[100005];

llint pow(llint a, llint n)
{
	if(n == 0) return 1;
	if(n % 2){
		return ((a%mod) * (pow(a, n-1)%mod)) % mod;
	}
	else{
		return pow((a*a)%mod, n/2) % mod;
	}
}

void make_fact()
{
	llint val = 1;
	fact[0] = 1;
	for(int i = 1; i < 100005; i++){
		val *= i;
		val %= mod;
		fact[i] = val;
	}
	for(int i = 0; i < 100005; i++){
		fact_inv[i] = pow(fact[i], mod-2);
	}
}

llint comb(llint n, llint k)
{
	llint ret = 1;
	ret *= fact[n];
	ret *= fact_inv[k], ret %= mod;
	ret *= fact_inv[n-k], ret %= mod;
	return ret;
}

llint N, K;
SegTree seg[2] = {SegTree(17), SegTree(17)};

int main(void)
{
	make_fact();
	cin >> N >> K;
	
	seg[0].update(0, 1);
	for(int i = 1; i <= K-1; i++){
		seg[i%2].init();
		for(int j = 0; j <= K-1; j++){
			llint tmp = 0;
			tmp += seg[(i+1)%2].query(j+1, j+1);
			if(K-(i+j) > 0) tmp += seg[(i+1)%2].query(j, j), tmp %= mod;
			if(j <= K-1-i) tmp += seg[(i+1)%2].query(0, j-1), tmp %= mod;
			seg[i%2].update(j, tmp);
			//cout << tmp << " ";
		}
		//cout << endl;
	}
	
	llint ans = seg[(K-1)%2].query(0, 0);
	ans *= comb(N-1, K-1), ans %= mod;
	ans *= pow(2, max(N-K-1, 0LL)), ans %= mod;
	cout << ans << endl;
	return 0;
}

Submission Info

Submission Time
Task F - Solitaire
User leaf1415
Language C++14 (GCC 5.4.1)
Score 0
Code Size 2105 Byte
Status WA
Exec Time 1912 ms
Memory 7936 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 1200
Status
AC × 2
WA × 1
AC × 9
WA × 17
Set Name Test Cases
Sample 00_example_01.txt, 00_example_02.txt, 00_example_03.txt
All 00_example_01.txt, 00_example_02.txt, 00_example_03.txt, 01.txt, 02.txt, 03.txt, 04.txt, 05.txt, 06.txt, 07.txt, 08.txt, 09.txt, 10.txt, 11.txt, 12.txt, 13.txt, 14.txt, 15.txt, 16.txt, 17.txt, 18.txt, 19.txt, 20.txt, 21.txt, 22.txt, 23.txt
Case Name Status Exec Time Memory
00_example_01.txt AC 40 ms 5888 KB
00_example_02.txt AC 40 ms 5888 KB
00_example_03.txt WA 555 ms 5888 KB
01.txt WA 41 ms 5888 KB
02.txt WA 418 ms 5888 KB
03.txt AC 45 ms 5888 KB
04.txt WA 58 ms 5888 KB
05.txt AC 40 ms 5888 KB
06.txt AC 40 ms 5888 KB
07.txt WA 41 ms 5888 KB
08.txt WA 43 ms 5888 KB
09.txt WA 1368 ms 7936 KB
10.txt WA 41 ms 5888 KB
11.txt AC 42 ms 5888 KB
12.txt WA 1541 ms 5888 KB
13.txt WA 47 ms 5888 KB
14.txt WA 294 ms 5888 KB
15.txt WA 188 ms 5888 KB
16.txt WA 306 ms 5888 KB
17.txt WA 220 ms 5888 KB
18.txt WA 783 ms 5888 KB
19.txt WA 624 ms 5888 KB
20.txt WA 178 ms 5888 KB
21.txt AC 40 ms 5888 KB
22.txt AC 1912 ms 5888 KB
23.txt AC 40 ms 5888 KB