oj.uz

Submission #353682

# Submission time Handle Problem Language Result Execution time Memory
353682 2021-01-21T09:26:34 Z shivensinha4 Tents (JOI18_tents) C++17
100 / 100
 251 ms 70892 KB 
#include "bits/stdc++.h"
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
#define endl '\n'

const ll mod = 1e9+7;

ll ncr(ll n, ll r) {
	if (r == 0) return 1;
	if (r == 1) return n;
	if (r == 2) return ((n*(n-1))/2 % mod);
	assert(false);
}

int main() {
#ifdef mlocal
	freopen("test.in", "r", stdin);
#endif
	
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	int n, m; cin >> n >> m;
	ll dp[n+1][m+1]; // [row][empty][light]
	memset(dp, 0, sizeof(dp));
	
	vector<ll> tp(m+1);
	tp[0] = 1;
	for_(i, 1, tp.size()) tp[i] = (4*tp[i-1]) % mod;
	for_(i, 0, m+1) dp[n][i] = 1;
	for (int i = n-1;  i >= 0; i--) {
		for_(emp, 0, m+1) {
			dp[i][emp] = dp[i+1][emp];
			if (emp >= 2) {
				dp[i][emp] += ((dp[i+1][emp-2] * ncr(emp, 2)) % mod);
				if (dp[i][emp] >= mod) dp[i][emp] -= mod;
			}
			
			if (emp >= 1) {
				if (i < n-1) dp[i][emp] += (emp * (n-i-1) * dp[i+2][emp-1]) % mod;
				if (dp[i][emp] >= mod) dp[i][emp] -= mod;
				dp[i][emp] += (((dp[i+1][emp-1] * 4) % mod) * emp) % mod;
				if (dp[i][emp] >= mod) dp[i][emp] -= mod;
			}
		}
	}
	
	cout << (dp[0][m]-1+mod) % mod << endl;
	
	
	return 0;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 492 KB Output is correct
7 Correct 2 ms 492 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 2 ms 620 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 3 ms 1004 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 492 KB Output is correct
7 Correct 2 ms 492 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 2 ms 620 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 3 ms 1004 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 163 ms 44140 KB Output is correct
16 Correct 11 ms 3180 KB Output is correct
17 Correct 39 ms 10092 KB Output is correct
18 Correct 46 ms 12524 KB Output is correct
19 Correct 201 ms 51564 KB Output is correct
20 Correct 159 ms 41096 KB Output is correct
21 Correct 95 ms 27244 KB Output is correct
22 Correct 96 ms 26860 KB Output is correct
23 Correct 54 ms 14956 KB Output is correct
24 Correct 251 ms 70892 KB Output is correct
25 Correct 182 ms 52588 KB Output is correct
26 Correct 223 ms 60268 KB Output is correct
27 Correct 237 ms 68204 KB Output is correct