#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
const ll md = 1e9+7;
ll pw(ll x, ll p){
if(!p) return 1;
if(p&1) return (pw(x, p-1)*x)%md;
return pw((x*x)%md, p>>1);
}
const int N = 500;
ll fac[N+5], facinv[N+5];
ll combiA[N+5][N+5], combiB[2*N+1][N+5];
ll dp[N][2*N+1], dp_sum[N][2*N+1], C[2*N+1][N+1];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
fac[0] = 1, facinv[0] = 1;
for(int i = 1; i < N+5; i++) fac[i] = (fac[i-1]*i)%md, facinv[i] = (facinv[i-1]*pw(i, md-2))%md;
int n; cin >> n;
vector<int> L(n), R(n);
vector<int> ranges, _ranges;
for(int i = 0; i < n; i++) cin >> L[i] >> R[i], _ranges.pb(L[i]), _ranges.pb(R[i]), _ranges.pb(R[i]+1);
sort(_ranges.begin(), _ranges.end());
for(int x: _ranges)
if(ranges.empty() || ranges.back() != x) ranges.pb(x);
int m = int(ranges.size())-1;
for(int i = 0; i <= n; i++) for(int j = 0; j <= i; j++){
combiA[i][j] = facinv[j];
for(int k = i-j+1; k <= i; k++) combiA[i][j]*=k, combiA[i][j]%=md;
}
for(int i = 0; i < m; i++){
int x = ranges[i+1]-ranges[i];
for(int j = 0; j <= n+1; j++){
if(j > x){
combiB[i][j] = 0;
continue;
}
combiB[i][j] = facinv[j];
for(int k = x-j+1; k <= x; k++) combiB[i][j]*=k, combiB[i][j]%=md;
}
}
for(int i = 0; i < m; i++){
for(int j = 0; j <= n; j++){
C[i][j] = 0;
for(int k = 0; k <= j; k++)
C[i][j]+=(combiA[j][k]*combiB[i][k+1])%md;
C[i][j]%=md;
}
}
auto nested = [&](int j, int i){
return ranges[j] >= L[i] && ranges[j+1]-1 <= R[i];
};
for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) dp[i][j] = 0, dp_sum[i][j] = 0;
for(int i = 0; i < n; i++){
for(int j = 0; j < m; j++){
if(!nested(j, i)) continue;
int c = 0;
for(int k = i; k >= 0; k--){
if(!nested(j, k)) c++;
if(j == 0 && k) continue;
dp[i][j]+=(C[j][i-k-c]*(k ? dp_sum[k-1][j-1]:1))%md;
dp[i][j]%=md;
}
}
for(int j = 0; j < m; j++){
if(j) dp_sum[i][j] = dp_sum[i][j-1];
dp_sum[i][j]+=dp[i][j];
dp_sum[i][j]%=md;
}
}
ll ans = 0;
for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) ans+=dp[i][j], ans%=md;
cout << ans << "\n";
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:56:13: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
56 | for(int k = 0; k <= j; k++)
| ^~~
boat.cpp:58:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
58 | C[i][j]%=md;
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
597 ms |
18068 KB |
Output is correct |
2 |
Correct |
643 ms |
17976 KB |
Output is correct |
3 |
Correct |
667 ms |
18060 KB |
Output is correct |
4 |
Correct |
661 ms |
17940 KB |
Output is correct |
5 |
Correct |
649 ms |
18008 KB |
Output is correct |
6 |
Correct |
642 ms |
17944 KB |
Output is correct |
7 |
Correct |
640 ms |
17996 KB |
Output is correct |
8 |
Correct |
616 ms |
18036 KB |
Output is correct |
9 |
Correct |
654 ms |
18000 KB |
Output is correct |
10 |
Correct |
690 ms |
17968 KB |
Output is correct |
11 |
Correct |
657 ms |
17976 KB |
Output is correct |
12 |
Correct |
656 ms |
17916 KB |
Output is correct |
13 |
Correct |
769 ms |
17964 KB |
Output is correct |
14 |
Correct |
657 ms |
17992 KB |
Output is correct |
15 |
Correct |
679 ms |
17992 KB |
Output is correct |
16 |
Correct |
223 ms |
9076 KB |
Output is correct |
17 |
Correct |
249 ms |
9240 KB |
Output is correct |
18 |
Correct |
213 ms |
9176 KB |
Output is correct |
19 |
Correct |
214 ms |
9312 KB |
Output is correct |
20 |
Correct |
234 ms |
9100 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
597 ms |
18068 KB |
Output is correct |
2 |
Correct |
643 ms |
17976 KB |
Output is correct |
3 |
Correct |
667 ms |
18060 KB |
Output is correct |
4 |
Correct |
661 ms |
17940 KB |
Output is correct |
5 |
Correct |
649 ms |
18008 KB |
Output is correct |
6 |
Correct |
642 ms |
17944 KB |
Output is correct |
7 |
Correct |
640 ms |
17996 KB |
Output is correct |
8 |
Correct |
616 ms |
18036 KB |
Output is correct |
9 |
Correct |
654 ms |
18000 KB |
Output is correct |
10 |
Correct |
690 ms |
17968 KB |
Output is correct |
11 |
Correct |
657 ms |
17976 KB |
Output is correct |
12 |
Correct |
656 ms |
17916 KB |
Output is correct |
13 |
Correct |
769 ms |
17964 KB |
Output is correct |
14 |
Correct |
657 ms |
17992 KB |
Output is correct |
15 |
Correct |
679 ms |
17992 KB |
Output is correct |
16 |
Correct |
223 ms |
9076 KB |
Output is correct |
17 |
Correct |
249 ms |
9240 KB |
Output is correct |
18 |
Correct |
213 ms |
9176 KB |
Output is correct |
19 |
Correct |
214 ms |
9312 KB |
Output is correct |
20 |
Correct |
234 ms |
9100 KB |
Output is correct |
21 |
Incorrect |
867 ms |
18052 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
16 ms |
4308 KB |
Output is correct |
2 |
Correct |
15 ms |
4308 KB |
Output is correct |
3 |
Correct |
17 ms |
4380 KB |
Output is correct |
4 |
Correct |
16 ms |
4324 KB |
Output is correct |
5 |
Correct |
16 ms |
4384 KB |
Output is correct |
6 |
Correct |
21 ms |
4300 KB |
Output is correct |
7 |
Correct |
18 ms |
4308 KB |
Output is correct |
8 |
Correct |
18 ms |
4308 KB |
Output is correct |
9 |
Correct |
20 ms |
4344 KB |
Output is correct |
10 |
Correct |
19 ms |
4364 KB |
Output is correct |
11 |
Correct |
20 ms |
4328 KB |
Output is correct |
12 |
Correct |
18 ms |
4352 KB |
Output is correct |
13 |
Correct |
14 ms |
4304 KB |
Output is correct |
14 |
Correct |
14 ms |
4308 KB |
Output is correct |
15 |
Correct |
15 ms |
4388 KB |
Output is correct |
16 |
Correct |
10 ms |
2896 KB |
Output is correct |
17 |
Correct |
10 ms |
2836 KB |
Output is correct |
18 |
Correct |
8 ms |
2772 KB |
Output is correct |
19 |
Correct |
10 ms |
2784 KB |
Output is correct |
20 |
Correct |
11 ms |
2868 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
597 ms |
18068 KB |
Output is correct |
2 |
Correct |
643 ms |
17976 KB |
Output is correct |
3 |
Correct |
667 ms |
18060 KB |
Output is correct |
4 |
Correct |
661 ms |
17940 KB |
Output is correct |
5 |
Correct |
649 ms |
18008 KB |
Output is correct |
6 |
Correct |
642 ms |
17944 KB |
Output is correct |
7 |
Correct |
640 ms |
17996 KB |
Output is correct |
8 |
Correct |
616 ms |
18036 KB |
Output is correct |
9 |
Correct |
654 ms |
18000 KB |
Output is correct |
10 |
Correct |
690 ms |
17968 KB |
Output is correct |
11 |
Correct |
657 ms |
17976 KB |
Output is correct |
12 |
Correct |
656 ms |
17916 KB |
Output is correct |
13 |
Correct |
769 ms |
17964 KB |
Output is correct |
14 |
Correct |
657 ms |
17992 KB |
Output is correct |
15 |
Correct |
679 ms |
17992 KB |
Output is correct |
16 |
Correct |
223 ms |
9076 KB |
Output is correct |
17 |
Correct |
249 ms |
9240 KB |
Output is correct |
18 |
Correct |
213 ms |
9176 KB |
Output is correct |
19 |
Correct |
214 ms |
9312 KB |
Output is correct |
20 |
Correct |
234 ms |
9100 KB |
Output is correct |
21 |
Incorrect |
867 ms |
18052 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |