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Submission #390638

# Submission time Handle Problem Language Result Execution time Memory
390638 2021-04-16T12:39:28 Z Blagojce Boat (APIO16_boat) C++11
36 / 100
 2000 ms 408 KB 
#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)


using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const int i_inf = 1e9;
const ll inf = 1e10;
const ll mod = 1e9+7;
const ld eps = 1e-13;
const ld pi  = 3.14159265359;

mt19937 _rand(time(NULL));
clock_t z;

const int mxn = 1000;


ll modpow(ll x, ll n){
	if(n == 0) return 1%mod;
	ll u = modpow(x, n/2);
	u = (u * u) % mod;
	if(n % 2) u = (u * x) % mod;
	return u;
}
ll inverse(ll x){
	return modpow(x, mod-2);
}

ll fakt[mxn];
ll ifakt[mxn];

ll bc1(ll n, ll k){
	if(n < k) return inverse(0);
	return (fakt[n]*((ifakt[k]*ifakt[n-k]) % mod)) % mod;
}

ll precomp[mxn];

void pre(ll n){
	ll tot = 1;
	precomp[0] = 1;
	fr(i, 0, mxn-1){
		tot *= (n-i);
		tot %= mod;
		precomp[i+1] = tot;
	}
}


ll bc2(ll n, ll k){
	if(n < k) return 0;
	
	return (precomp[k]*ifakt[k])%mod;
}


int n;
ll l[mxn], r[mxn];

ll DP1[mxn];
ll DP2[mxn];


void solve(){
	fakt[0] = 1;
	fr(i, 1, mxn){
		fakt[i] = (fakt[i-1]*i)%mod;
	}
	fr(i, 0, mxn){
		ifakt[i] = inverse(fakt[i]);
	}
	
	
	
	cin >> n;
	fr(i, 0, n){
		cin >> l[i] >> r[i];
	}
	
	vector<pair<ll, int> > v;
	fr(i, 0, n){
		v.pb({l[i], -i});
		v.pb({r[i],i+1});
	}
	
	sort(all(v));
	
	vector<int> active;
	
	DP1[0] = 1;
	
	ll prv = 0;
	
	ll a_len;
	
	for(auto u : v){
		
		int id = u.nd;
		
		if(id > 0){
			a_len = u.st - prv;
		}
		else{
			a_len = u.st - prv-1;
		}
				
		fr(i, 0, mxn) DP2[i] = DP1[i];
		
		pre(a_len);
		
		
		fr(i, 0, (int)active.size()){
			ll sum = 0;
			fr(k, 0, active[i]+1){
				sum += DP1[k];
				sum %= mod;
			}
			
			fr(j, i, (int)active.size()){
				int psz = 1 + (int)(i != j);
				
				
				fr(len, psz, j-i+2){
					
					ll ways = (bc2(a_len, len)*bc1(j-i+1-psz, len-psz))%mod;
					
					DP2[active[j]+1] += (ways*sum)%mod;
					DP2[active[j]+1] %= mod;
				}
			}
		}
		
		fr(i, 0, mxn){
			DP1[i] = DP2[i];
		}
		
		if(id <= 0){
			prv = u.st-1; 
			active.pb(-id);
			sort(all(active));
			
		}else{
			prv = u.st;
			active.erase(find(all(active), id-1));
			sort(all(active));
		}
		
		
	}
	ll ans = 0;
	fr(i, 1, n+1){
		ans += DP1[i];
		ans %= mod;
	}
	
	cout<<ans<<endl;
	
}

int main(){
	
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	solve();
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 332 KB Output is correct
2 Correct 8 ms 332 KB Output is correct
3 Correct 9 ms 332 KB Output is correct
4 Correct 8 ms 332 KB Output is correct
5 Correct 8 ms 332 KB Output is correct
6 Correct 8 ms 332 KB Output is correct
7 Correct 8 ms 336 KB Output is correct
8 Correct 8 ms 404 KB Output is correct
9 Correct 8 ms 332 KB Output is correct
10 Correct 8 ms 336 KB Output is correct
11 Correct 8 ms 332 KB Output is correct
12 Correct 8 ms 332 KB Output is correct
13 Correct 8 ms 332 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 8 ms 408 KB Output is correct
16 Correct 14 ms 404 KB Output is correct
17 Correct 14 ms 408 KB Output is correct
18 Correct 15 ms 332 KB Output is correct
19 Correct 15 ms 332 KB Output is correct
20 Correct 14 ms 336 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 332 KB Output is correct
2 Correct 8 ms 332 KB Output is correct
3 Correct 9 ms 332 KB Output is correct
4 Correct 8 ms 332 KB Output is correct
5 Correct 8 ms 332 KB Output is correct
6 Correct 8 ms 332 KB Output is correct
7 Correct 8 ms 336 KB Output is correct
8 Correct 8 ms 404 KB Output is correct
9 Correct 8 ms 332 KB Output is correct
10 Correct 8 ms 336 KB Output is correct
11 Correct 8 ms 332 KB Output is correct
12 Correct 8 ms 332 KB Output is correct
13 Correct 8 ms 332 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 8 ms 408 KB Output is correct
16 Correct 14 ms 404 KB Output is correct
17 Correct 14 ms 408 KB Output is correct
18 Correct 15 ms 332 KB Output is correct
19 Correct 15 ms 332 KB Output is correct
20 Correct 14 ms 336 KB Output is correct
21 Execution timed out 2082 ms 332 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 47 ms 332 KB Output is correct
2 Correct 25 ms 340 KB Output is correct
3 Correct 37 ms 332 KB Output is correct
4 Correct 44 ms 356 KB Output is correct
5 Correct 49 ms 336 KB Output is correct
6 Correct 172 ms 332 KB Output is correct
7 Correct 168 ms 356 KB Output is correct
8 Correct 165 ms 356 KB Output is correct
9 Correct 162 ms 356 KB Output is correct
10 Correct 163 ms 332 KB Output is correct
11 Correct 52 ms 332 KB Output is correct
12 Correct 30 ms 332 KB Output is correct
13 Correct 39 ms 332 KB Output is correct
14 Correct 38 ms 332 KB Output is correct
15 Correct 49 ms 352 KB Output is correct
16 Correct 44 ms 332 KB Output is correct
17 Correct 35 ms 332 KB Output is correct
18 Correct 43 ms 332 KB Output is correct
19 Correct 36 ms 368 KB Output is correct
20 Correct 48 ms 332 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 332 KB Output is correct
2 Correct 8 ms 332 KB Output is correct
3 Correct 9 ms 332 KB Output is correct
4 Correct 8 ms 332 KB Output is correct
5 Correct 8 ms 332 KB Output is correct
6 Correct 8 ms 332 KB Output is correct
7 Correct 8 ms 336 KB Output is correct
8 Correct 8 ms 404 KB Output is correct
9 Correct 8 ms 332 KB Output is correct
10 Correct 8 ms 336 KB Output is correct
11 Correct 8 ms 332 KB Output is correct
12 Correct 8 ms 332 KB Output is correct
13 Correct 8 ms 332 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 8 ms 408 KB Output is correct
16 Correct 14 ms 404 KB Output is correct
17 Correct 14 ms 408 KB Output is correct
18 Correct 15 ms 332 KB Output is correct
19 Correct 15 ms 332 KB Output is correct
20 Correct 14 ms 336 KB Output is correct
21 Execution timed out 2082 ms 332 KB Time limit exceeded
22 Halted 0 ms 0 KB -