#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(j == 0 && k) continue;
if(!nested(j, k)) c++;
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 |
673 ms |
17980 KB |
Output is correct |
2 |
Correct |
687 ms |
18124 KB |
Output is correct |
3 |
Correct |
638 ms |
18044 KB |
Output is correct |
4 |
Correct |
716 ms |
18008 KB |
Output is correct |
5 |
Correct |
773 ms |
18008 KB |
Output is correct |
6 |
Correct |
675 ms |
17984 KB |
Output is correct |
7 |
Correct |
615 ms |
18008 KB |
Output is correct |
8 |
Correct |
625 ms |
18120 KB |
Output is correct |
9 |
Correct |
596 ms |
17996 KB |
Output is correct |
10 |
Correct |
599 ms |
18048 KB |
Output is correct |
11 |
Correct |
583 ms |
18024 KB |
Output is correct |
12 |
Correct |
602 ms |
18008 KB |
Output is correct |
13 |
Correct |
603 ms |
18000 KB |
Output is correct |
14 |
Correct |
608 ms |
18008 KB |
Output is correct |
15 |
Correct |
574 ms |
18020 KB |
Output is correct |
16 |
Correct |
191 ms |
9084 KB |
Output is correct |
17 |
Correct |
186 ms |
9276 KB |
Output is correct |
18 |
Correct |
187 ms |
9124 KB |
Output is correct |
19 |
Correct |
186 ms |
9184 KB |
Output is correct |
20 |
Correct |
187 ms |
9180 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
673 ms |
17980 KB |
Output is correct |
2 |
Correct |
687 ms |
18124 KB |
Output is correct |
3 |
Correct |
638 ms |
18044 KB |
Output is correct |
4 |
Correct |
716 ms |
18008 KB |
Output is correct |
5 |
Correct |
773 ms |
18008 KB |
Output is correct |
6 |
Correct |
675 ms |
17984 KB |
Output is correct |
7 |
Correct |
615 ms |
18008 KB |
Output is correct |
8 |
Correct |
625 ms |
18120 KB |
Output is correct |
9 |
Correct |
596 ms |
17996 KB |
Output is correct |
10 |
Correct |
599 ms |
18048 KB |
Output is correct |
11 |
Correct |
583 ms |
18024 KB |
Output is correct |
12 |
Correct |
602 ms |
18008 KB |
Output is correct |
13 |
Correct |
603 ms |
18000 KB |
Output is correct |
14 |
Correct |
608 ms |
18008 KB |
Output is correct |
15 |
Correct |
574 ms |
18020 KB |
Output is correct |
16 |
Correct |
191 ms |
9084 KB |
Output is correct |
17 |
Correct |
186 ms |
9276 KB |
Output is correct |
18 |
Correct |
187 ms |
9124 KB |
Output is correct |
19 |
Correct |
186 ms |
9184 KB |
Output is correct |
20 |
Correct |
187 ms |
9180 KB |
Output is correct |
21 |
Incorrect |
726 ms |
18040 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
14 ms |
4308 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
673 ms |
17980 KB |
Output is correct |
2 |
Correct |
687 ms |
18124 KB |
Output is correct |
3 |
Correct |
638 ms |
18044 KB |
Output is correct |
4 |
Correct |
716 ms |
18008 KB |
Output is correct |
5 |
Correct |
773 ms |
18008 KB |
Output is correct |
6 |
Correct |
675 ms |
17984 KB |
Output is correct |
7 |
Correct |
615 ms |
18008 KB |
Output is correct |
8 |
Correct |
625 ms |
18120 KB |
Output is correct |
9 |
Correct |
596 ms |
17996 KB |
Output is correct |
10 |
Correct |
599 ms |
18048 KB |
Output is correct |
11 |
Correct |
583 ms |
18024 KB |
Output is correct |
12 |
Correct |
602 ms |
18008 KB |
Output is correct |
13 |
Correct |
603 ms |
18000 KB |
Output is correct |
14 |
Correct |
608 ms |
18008 KB |
Output is correct |
15 |
Correct |
574 ms |
18020 KB |
Output is correct |
16 |
Correct |
191 ms |
9084 KB |
Output is correct |
17 |
Correct |
186 ms |
9276 KB |
Output is correct |
18 |
Correct |
187 ms |
9124 KB |
Output is correct |
19 |
Correct |
186 ms |
9184 KB |
Output is correct |
20 |
Correct |
187 ms |
9180 KB |
Output is correct |
21 |
Incorrect |
726 ms |
18040 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |