#include<bits/stdc++.h>
using namespace std;
const int N = 505;
const int mod = 1e9 + 7;
void add(int &a,int b) {
a += b;
if (a >= mod)
a -= mod;
}
void sub(int &a,int b) {
a -= b;
if (a < 0)
a += mod;
}
int mul(int a,int b) {
return 1ll * a * b % mod;
}
int inv[N];
int a[N], b[N];
int f[N][1010];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
inv[1] = 1;
for(int i = 2 ; i < N ; ++i)
inv[i] = mul(inv[mod % i],mod - mod / i);
int n; cin >> n;
vector<int> comp;
for(int i = 1 ; i <= n ; ++i) {
cin >> a[i]; comp.push_back(a[i] - 1);
cin >> b[i]; comp.push_back(b[i]);
}
sort(comp.begin(),comp.end());
comp.erase(unique(comp.begin(),comp.end()),comp.end());
for(int i = 1 ; i <= n ; ++i) {
a[i] = lower_bound(comp.begin(),comp.end(),a[i]) - comp.begin();
b[i] = lower_bound(comp.begin(),comp.end(),b[i]) - comp.begin();
}
for(int i = 0 ; i < comp.size() ; ++i)
f[0][i] = 1;
for(int i = 1 ; i <= n ; ++i) {
assert(a[i]);
f[i][0] = 1;
for(int j = a[i] ; j <= b[i] ; ++j) {
f[i][j] = mul(f[i - 1][j - 1],comp[j] - comp[j - 1]);
int cnt = 1;
int Max = comp[j] - comp[j - 1];
int way = Max - 1;
for(int k = i - 1 ; k ; --k) if (a[k] <= j && j <= b[k]) {
way = mul(way,Max++);
way = mul(way,inv[++cnt]);
add(f[i][j],mul(f[k - 1][j - 1],way));
}
}
for(int j = 1 ; j < comp.size() ; ++j)
//cout << f[i][j] << " ",
add(f[i][j],f[i - 1][j]),
add(f[i][j],f[i][j - 1]),
sub(f[i][j],f[i - 1][j - 1]);
//cout << "\n";
}
int ans = f[n][comp.size() - 1];
sub(ans,1);
cout << ans << endl;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:51:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0 ; i < comp.size() ; ++i)
~~^~~~~~~~~~~~~
boat.cpp:70:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 1 ; j < comp.size() ; ++j)
~~^~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 2 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 3 |
Correct |
7 ms |
2168 KB |
Output is correct |
| 4 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 5 |
Correct |
7 ms |
2312 KB |
Output is correct |
| 6 |
Correct |
7 ms |
2300 KB |
Output is correct |
| 7 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 8 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 9 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 10 |
Correct |
8 ms |
2296 KB |
Output is correct |
| 11 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 12 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 13 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 14 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 15 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 16 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 17 |
Correct |
5 ms |
2300 KB |
Output is correct |
| 18 |
Correct |
5 ms |
2424 KB |
Output is correct |
| 19 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 20 |
Correct |
5 ms |
2300 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 2 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 3 |
Correct |
7 ms |
2168 KB |
Output is correct |
| 4 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 5 |
Correct |
7 ms |
2312 KB |
Output is correct |
| 6 |
Correct |
7 ms |
2300 KB |
Output is correct |
| 7 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 8 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 9 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 10 |
Correct |
8 ms |
2296 KB |
Output is correct |
| 11 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 12 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 13 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 14 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 15 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 16 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 17 |
Correct |
5 ms |
2300 KB |
Output is correct |
| 18 |
Correct |
5 ms |
2424 KB |
Output is correct |
| 19 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 20 |
Correct |
5 ms |
2300 KB |
Output is correct |
| 21 |
Correct |
447 ms |
2372 KB |
Output is correct |
| 22 |
Correct |
433 ms |
2456 KB |
Output is correct |
| 23 |
Correct |
387 ms |
2464 KB |
Output is correct |
| 24 |
Correct |
434 ms |
2424 KB |
Output is correct |
| 25 |
Correct |
445 ms |
2412 KB |
Output is correct |
| 26 |
Correct |
779 ms |
2468 KB |
Output is correct |
| 27 |
Correct |
721 ms |
2328 KB |
Output is correct |
| 28 |
Correct |
727 ms |
2420 KB |
Output is correct |
| 29 |
Correct |
713 ms |
2536 KB |
Output is correct |
| 30 |
Correct |
8 ms |
2292 KB |
Output is correct |
| 31 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 32 |
Correct |
14 ms |
2296 KB |
Output is correct |
| 33 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 34 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 35 |
Correct |
9 ms |
2424 KB |
Output is correct |
| 36 |
Correct |
9 ms |
2296 KB |
Output is correct |
| 37 |
Correct |
9 ms |
2296 KB |
Output is correct |
| 38 |
Correct |
9 ms |
2300 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
6 ms |
760 KB |
Output is correct |
| 2 |
Correct |
5 ms |
760 KB |
Output is correct |
| 3 |
Correct |
6 ms |
760 KB |
Output is correct |
| 4 |
Correct |
6 ms |
760 KB |
Output is correct |
| 5 |
Correct |
6 ms |
760 KB |
Output is correct |
| 6 |
Correct |
9 ms |
760 KB |
Output is correct |
| 7 |
Correct |
10 ms |
760 KB |
Output is correct |
| 8 |
Correct |
10 ms |
760 KB |
Output is correct |
| 9 |
Correct |
11 ms |
760 KB |
Output is correct |
| 10 |
Correct |
10 ms |
760 KB |
Output is correct |
| 11 |
Correct |
7 ms |
760 KB |
Output is correct |
| 12 |
Correct |
5 ms |
760 KB |
Output is correct |
| 13 |
Correct |
6 ms |
760 KB |
Output is correct |
| 14 |
Correct |
6 ms |
760 KB |
Output is correct |
| 15 |
Correct |
20 ms |
760 KB |
Output is correct |
| 16 |
Correct |
5 ms |
760 KB |
Output is correct |
| 17 |
Correct |
4 ms |
760 KB |
Output is correct |
| 18 |
Correct |
4 ms |
760 KB |
Output is correct |
| 19 |
Correct |
4 ms |
760 KB |
Output is correct |
| 20 |
Correct |
5 ms |
760 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 2 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 3 |
Correct |
7 ms |
2168 KB |
Output is correct |
| 4 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 5 |
Correct |
7 ms |
2312 KB |
Output is correct |
| 6 |
Correct |
7 ms |
2300 KB |
Output is correct |
| 7 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 8 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 9 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 10 |
Correct |
8 ms |
2296 KB |
Output is correct |
| 11 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 12 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 13 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 14 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 15 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 16 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 17 |
Correct |
5 ms |
2300 KB |
Output is correct |
| 18 |
Correct |
5 ms |
2424 KB |
Output is correct |
| 19 |
Correct |
5 ms |
2296 KB |
Output is correct |
| 20 |
Correct |
5 ms |
2300 KB |
Output is correct |
| 21 |
Correct |
447 ms |
2372 KB |
Output is correct |
| 22 |
Correct |
433 ms |
2456 KB |
Output is correct |
| 23 |
Correct |
387 ms |
2464 KB |
Output is correct |
| 24 |
Correct |
434 ms |
2424 KB |
Output is correct |
| 25 |
Correct |
445 ms |
2412 KB |
Output is correct |
| 26 |
Correct |
779 ms |
2468 KB |
Output is correct |
| 27 |
Correct |
721 ms |
2328 KB |
Output is correct |
| 28 |
Correct |
727 ms |
2420 KB |
Output is correct |
| 29 |
Correct |
713 ms |
2536 KB |
Output is correct |
| 30 |
Correct |
8 ms |
2292 KB |
Output is correct |
| 31 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 32 |
Correct |
14 ms |
2296 KB |
Output is correct |
| 33 |
Correct |
7 ms |
2296 KB |
Output is correct |
| 34 |
Correct |
7 ms |
2424 KB |
Output is correct |
| 35 |
Correct |
9 ms |
2424 KB |
Output is correct |
| 36 |
Correct |
9 ms |
2296 KB |
Output is correct |
| 37 |
Correct |
9 ms |
2296 KB |
Output is correct |
| 38 |
Correct |
9 ms |
2300 KB |
Output is correct |
| 39 |
Correct |
6 ms |
760 KB |
Output is correct |
| 40 |
Correct |
5 ms |
760 KB |
Output is correct |
| 41 |
Correct |
6 ms |
760 KB |
Output is correct |
| 42 |
Correct |
6 ms |
760 KB |
Output is correct |
| 43 |
Correct |
6 ms |
760 KB |
Output is correct |
| 44 |
Correct |
9 ms |
760 KB |
Output is correct |
| 45 |
Correct |
10 ms |
760 KB |
Output is correct |
| 46 |
Correct |
10 ms |
760 KB |
Output is correct |
| 47 |
Correct |
11 ms |
760 KB |
Output is correct |
| 48 |
Correct |
10 ms |
760 KB |
Output is correct |
| 49 |
Correct |
7 ms |
760 KB |
Output is correct |
| 50 |
Correct |
5 ms |
760 KB |
Output is correct |
| 51 |
Correct |
6 ms |
760 KB |
Output is correct |
| 52 |
Correct |
6 ms |
760 KB |
Output is correct |
| 53 |
Correct |
20 ms |
760 KB |
Output is correct |
| 54 |
Correct |
5 ms |
760 KB |
Output is correct |
| 55 |
Correct |
4 ms |
760 KB |
Output is correct |
| 56 |
Correct |
4 ms |
760 KB |
Output is correct |
| 57 |
Correct |
4 ms |
760 KB |
Output is correct |
| 58 |
Correct |
5 ms |
760 KB |
Output is correct |
| 59 |
Correct |
696 ms |
2424 KB |
Output is correct |
| 60 |
Correct |
463 ms |
2552 KB |
Output is correct |
| 61 |
Correct |
440 ms |
2384 KB |
Output is correct |
| 62 |
Correct |
520 ms |
2424 KB |
Output is correct |
| 63 |
Correct |
485 ms |
2348 KB |
Output is correct |
| 64 |
Correct |
913 ms |
2440 KB |
Output is correct |
| 65 |
Correct |
860 ms |
2424 KB |
Output is correct |
| 66 |
Correct |
893 ms |
2452 KB |
Output is correct |
| 67 |
Correct |
865 ms |
2424 KB |
Output is correct |
| 68 |
Correct |
880 ms |
2464 KB |
Output is correct |
| 69 |
Correct |
404 ms |
2336 KB |
Output is correct |
| 70 |
Correct |
395 ms |
2392 KB |
Output is correct |
| 71 |
Correct |
390 ms |
2520 KB |
Output is correct |
| 72 |
Correct |
421 ms |
2284 KB |
Output is correct |
| 73 |
Correct |
406 ms |
2424 KB |
Output is correct |
| 74 |
Correct |
89 ms |
2296 KB |
Output is correct |
| 75 |
Correct |
83 ms |
2300 KB |
Output is correct |
| 76 |
Correct |
88 ms |
2296 KB |
Output is correct |
| 77 |
Correct |
91 ms |
2296 KB |
Output is correct |
| 78 |
Correct |
93 ms |
2312 KB |
Output is correct |
