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Submission #390633

# Submission time Handle Problem Language Result Execution time Memory
390633 2021-04-16T12:24:19 Z Blagojce Boat (APIO16_boat) C++11
9 / 100
 2000 ms 452 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];

int DP1[mxn];
int 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<int,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(i-j+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, 0, n+1){
		ans += DP1[i];
		ans %= mod;
	}
	--ans;
	if(ans < 0) 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 9 ms 388 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 9 ms 332 KB Output is correct
7 Correct 9 ms 332 KB Output is correct
8 Correct 9 ms 384 KB Output is correct
9 Correct 9 ms 332 KB Output is correct
10 Correct 9 ms 332 KB Output is correct
11 Correct 9 ms 332 KB Output is correct
12 Correct 9 ms 380 KB Output is correct
13 Correct 9 ms 388 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 9 ms 380 KB Output is correct
16 Correct 21 ms 380 KB Output is correct
17 Correct 22 ms 452 KB Output is correct
18 Correct 22 ms 332 KB Output is correct
19 Correct 22 ms 332 KB Output is correct
20 Correct 20 ms 384 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 9 ms 388 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 9 ms 332 KB Output is correct
7 Correct 9 ms 332 KB Output is correct
8 Correct 9 ms 384 KB Output is correct
9 Correct 9 ms 332 KB Output is correct
10 Correct 9 ms 332 KB Output is correct
11 Correct 9 ms 332 KB Output is correct
12 Correct 9 ms 380 KB Output is correct
13 Correct 9 ms 388 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 9 ms 380 KB Output is correct
16 Correct 21 ms 380 KB Output is correct
17 Correct 22 ms 452 KB Output is correct
18 Correct 22 ms 332 KB Output is correct
19 Correct 22 ms 332 KB Output is correct
20 Correct 20 ms 384 KB Output is correct
21 Execution timed out 2079 ms 332 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 459 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 332 KB Output is correct
2 Correct 9 ms 388 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 9 ms 332 KB Output is correct
7 Correct 9 ms 332 KB Output is correct
8 Correct 9 ms 384 KB Output is correct
9 Correct 9 ms 332 KB Output is correct
10 Correct 9 ms 332 KB Output is correct
11 Correct 9 ms 332 KB Output is correct
12 Correct 9 ms 380 KB Output is correct
13 Correct 9 ms 388 KB Output is correct
14 Correct 9 ms 332 KB Output is correct
15 Correct 9 ms 380 KB Output is correct
16 Correct 21 ms 380 KB Output is correct
17 Correct 22 ms 452 KB Output is correct
18 Correct 22 ms 332 KB Output is correct
19 Correct 22 ms 332 KB Output is correct
20 Correct 20 ms 384 KB Output is correct
21 Execution timed out 2079 ms 332 KB Time limit exceeded
22 Halted 0 ms 0 KB -