#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();
}
# |
결과 |
실행 시간 |
메모리 |
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 |
# |
결과 |
실행 시간 |
메모리 |
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 |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
459 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
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 |
- |