oj.uz

Submission #716375

# Submission time Handle Problem Language Result Execution time Memory
716375 2023-03-29T20:01:18 Z S2speed Tents (JOI18_tents) C++17
100 / 100
 166 ms 212880 KB 
#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("Ofast")

#define all(x) x.begin() , x.end()
#define sze(x) (ll)(x.size())
#define mp(x , y) make_pair(x , y)
#define wall cout<<"--------------------------------------\n";
typedef long long int ll;
typedef pair<ll , ll> pll;
typedef pair<int , int> pii;
typedef double db;
typedef pair<pll , ll> plll;
typedef pair<int , pii> piii;
typedef pair<pll , pll> pllll;

const ll maxn = 3e3 + 17 , md = 1e9 + 7 , inf = 2e16;

inline ll tav(ll n , ll k){
	ll res = 1;
	while(k > 0){
		if(k & 1){
			res *= n; res %= md;
		}
		n *= n; n %= md;
		k >>= 1;
	}
	return res;
}

ll fact[maxn] , _fact[maxn];

void fact_build(){
	fact[0] = 1;
	for(ll i = 1 ; i < maxn ; i++){
		fact[i] = fact[i - 1] * i % md;
	}
	_fact[maxn - 1] = tav(fact[maxn - 1] , md - 2);
	for(ll i = maxn - 2 ; ~i ; i--){
		_fact[i] = _fact[i + 1] * (i + 1) % md;
	}
	return;
}

ll chs(ll n , ll k){
	if(k < 0 || k > n) return 0;
	return fact[n] * _fact[k] % md * _fact[n - k] % md;
}

ll dp[maxn][maxn] , ps[maxn][maxn] , ps2[maxn][maxn];

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	fact_build();
	ll n , m;
	cin>>n>>m;
	fill(dp[0] , dp[0] + m + 1 , 1);
	iota(ps[0] , ps[0] + m + 1 , 1);
	for(ll i = 0 ; i <= m ; i++){
		ps2[0][i] = (i + 2) * (i + 1) / 2;
	}
	for(ll i = 1 ; i <= n ; i++){
		ps2[i][0] = ps[i][0] = dp[i][0] = 1;
		for(ll j = 1 ; j <= m ; j++){
			ll h = 1;
			if(j > 1){
				h += ps2[i - 1][j - 2] * i % md;
			}
			if(i > 1){
				h += chs(i , 2) * ps[i - 2][j - 1] % md;
			}
			dp[i][j] = h % md;
			ps[i][j] = ps[i][j - 1] + dp[i][j]; ps[i][j] %= md;
			ps2[i][j] = ps2[i][j - 1] + dp[i][j] * (j + 1); ps2[i][j] %= md;
		}
	}
	ll ans = -1 , lm = min(n , m);
	for(ll i = 0 ; i <= lm ; i++){
		ll h = chs(n , i) * chs(m , i) % md * fact[i] % md * dp[n - i][m - i] % md * tav(4 , i) % md;
		ans += h;
	}
	ans %= md;
	cout<<ans<<'\n';
	return 0;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 852 KB Output is correct
4 Correct 2 ms 2900 KB Output is correct
5 Correct 1 ms 1492 KB Output is correct
6 Correct 2 ms 3540 KB Output is correct
7 Correct 1 ms 1908 KB Output is correct
8 Correct 2 ms 3796 KB Output is correct
9 Correct 2 ms 1876 KB Output is correct
10 Correct 2 ms 4820 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 4 ms 6228 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 852 KB Output is correct
4 Correct 2 ms 2900 KB Output is correct
5 Correct 1 ms 1492 KB Output is correct
6 Correct 2 ms 3540 KB Output is correct
7 Correct 1 ms 1908 KB Output is correct
8 Correct 2 ms 3796 KB Output is correct
9 Correct 2 ms 1876 KB Output is correct
10 Correct 2 ms 4820 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 4 ms 6228 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 10 ms 28372 KB Output is correct
15 Correct 103 ms 164948 KB Output is correct
16 Correct 8 ms 11532 KB Output is correct
17 Correct 31 ms 37964 KB Output is correct
18 Correct 33 ms 50676 KB Output is correct
19 Correct 119 ms 188464 KB Output is correct
20 Correct 103 ms 152048 KB Output is correct
21 Correct 70 ms 100852 KB Output is correct
22 Correct 69 ms 105860 KB Output is correct
23 Correct 47 ms 80592 KB Output is correct
24 Correct 166 ms 212880 KB Output is correct
25 Correct 134 ms 183920 KB Output is correct
26 Correct 140 ms 200168 KB Output is correct
27 Correct 164 ms 207212 KB Output is correct