#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
typedef long long ll;
const int maxn = 1005;
const int mod = 1e9+7;
int n;
pair<int, int> A[maxn];
vector<int> cp;
ll dp[maxn][2*maxn], pc[2*maxn][maxn], inv[maxn];
int main(){
inv[0] = inv[1] = 1;
for(int i = 2; i < maxn; i++)inv[i]=mod - inv[mod%i]*(mod/i)%mod;
cin >> n;
for(int i = 1; i <= n; i++){
cin >> A[i].f >> A[i].s;
cp.push_back(A[i].f-1);
cp.push_back(A[i].s);
}
cp.push_back(0);
sort(cp.begin(), cp.end());
cp.erase(unique(cp.begin(), cp.end()), cp.end());
for(int i = 1; i < cp.size(); i++){
ll len = cp[i]-cp[i-1];
pc[i][1] = len;
for(int j = 2; j <= n; j++){
ll crr = len*(len-1)/2;
crr%=mod;
for(int k = 2; k <= min({n, int(len), j}); k++){
pc[i][j] += crr;
// C(k-2, j)*C(k, len)
if(pc[i][j] >= mod)pc[i][j]-=mod;
k-=2;
crr=crr*(j-k)%mod;
crr=crr*inv[k+1]%mod;
k+=2;
crr=crr*(len-k)%mod;
crr=crr*inv[k+1]%mod;
}
}
}
for(int i = 0; i < cp.size(); i++)dp[0][i]=1;
for(int i = 0; i <= n; i++)dp[i][0]=1;
for(int i = 1; i <= n; i++){
for(int j = 1; j < cp.size(); j++){
if(A[i].f > cp[j] || A[i].s <= cp[j-1])dp[i][j]=0;
else{
int cnt = 0;
for(int k = i; k > 0; k--){
if(A[k].s >= cp[j] && A[k].f <= cp[j-1]+1){
cnt++;
dp[i][j]+=dp[k-1][j-1]*pc[j][cnt]%mod;
dp[i][j]%=mod;
}
}
}
dp[i][j]+=dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1];
dp[i][j]%=mod;
}
}
ll ans = dp[n][cp.size()-1]-1;
ans%=mod;
if(ans < 0)ans+=mod;
cout << ans;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:32:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
32 | for(int i = 1; i < cp.size(); i++){
| ~~^~~~~~~~~~~
boat.cpp:51:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
51 | for(int i = 0; i < cp.size(); i++)dp[0][i]=1;
| ~~^~~~~~~~~~~
boat.cpp:54:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
54 | for(int j = 1; j < cp.size(); j++){
| ~~^~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1121 ms |
12168 KB |
Output is correct |
2 |
Correct |
1127 ms |
12196 KB |
Output is correct |
3 |
Correct |
1132 ms |
12128 KB |
Output is correct |
4 |
Correct |
1131 ms |
12360 KB |
Output is correct |
5 |
Correct |
1130 ms |
12168 KB |
Output is correct |
6 |
Correct |
1131 ms |
12444 KB |
Output is correct |
7 |
Correct |
1129 ms |
12168 KB |
Output is correct |
8 |
Correct |
1133 ms |
12308 KB |
Output is correct |
9 |
Correct |
1133 ms |
12116 KB |
Output is correct |
10 |
Correct |
1133 ms |
12236 KB |
Output is correct |
11 |
Correct |
1130 ms |
12188 KB |
Output is correct |
12 |
Correct |
1128 ms |
12228 KB |
Output is correct |
13 |
Correct |
1129 ms |
12220 KB |
Output is correct |
14 |
Correct |
1133 ms |
12248 KB |
Output is correct |
15 |
Correct |
1133 ms |
12152 KB |
Output is correct |
16 |
Correct |
204 ms |
4008 KB |
Output is correct |
17 |
Correct |
216 ms |
4176 KB |
Output is correct |
18 |
Correct |
210 ms |
4076 KB |
Output is correct |
19 |
Correct |
218 ms |
4292 KB |
Output is correct |
20 |
Correct |
209 ms |
4080 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1121 ms |
12168 KB |
Output is correct |
2 |
Correct |
1127 ms |
12196 KB |
Output is correct |
3 |
Correct |
1132 ms |
12128 KB |
Output is correct |
4 |
Correct |
1131 ms |
12360 KB |
Output is correct |
5 |
Correct |
1130 ms |
12168 KB |
Output is correct |
6 |
Correct |
1131 ms |
12444 KB |
Output is correct |
7 |
Correct |
1129 ms |
12168 KB |
Output is correct |
8 |
Correct |
1133 ms |
12308 KB |
Output is correct |
9 |
Correct |
1133 ms |
12116 KB |
Output is correct |
10 |
Correct |
1133 ms |
12236 KB |
Output is correct |
11 |
Correct |
1130 ms |
12188 KB |
Output is correct |
12 |
Correct |
1128 ms |
12228 KB |
Output is correct |
13 |
Correct |
1129 ms |
12220 KB |
Output is correct |
14 |
Correct |
1133 ms |
12248 KB |
Output is correct |
15 |
Correct |
1133 ms |
12152 KB |
Output is correct |
16 |
Correct |
204 ms |
4008 KB |
Output is correct |
17 |
Correct |
216 ms |
4176 KB |
Output is correct |
18 |
Correct |
210 ms |
4076 KB |
Output is correct |
19 |
Correct |
218 ms |
4292 KB |
Output is correct |
20 |
Correct |
209 ms |
4080 KB |
Output is correct |
21 |
Incorrect |
155 ms |
12432 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
20 ms |
1740 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1121 ms |
12168 KB |
Output is correct |
2 |
Correct |
1127 ms |
12196 KB |
Output is correct |
3 |
Correct |
1132 ms |
12128 KB |
Output is correct |
4 |
Correct |
1131 ms |
12360 KB |
Output is correct |
5 |
Correct |
1130 ms |
12168 KB |
Output is correct |
6 |
Correct |
1131 ms |
12444 KB |
Output is correct |
7 |
Correct |
1129 ms |
12168 KB |
Output is correct |
8 |
Correct |
1133 ms |
12308 KB |
Output is correct |
9 |
Correct |
1133 ms |
12116 KB |
Output is correct |
10 |
Correct |
1133 ms |
12236 KB |
Output is correct |
11 |
Correct |
1130 ms |
12188 KB |
Output is correct |
12 |
Correct |
1128 ms |
12228 KB |
Output is correct |
13 |
Correct |
1129 ms |
12220 KB |
Output is correct |
14 |
Correct |
1133 ms |
12248 KB |
Output is correct |
15 |
Correct |
1133 ms |
12152 KB |
Output is correct |
16 |
Correct |
204 ms |
4008 KB |
Output is correct |
17 |
Correct |
216 ms |
4176 KB |
Output is correct |
18 |
Correct |
210 ms |
4076 KB |
Output is correct |
19 |
Correct |
218 ms |
4292 KB |
Output is correct |
20 |
Correct |
209 ms |
4080 KB |
Output is correct |
21 |
Incorrect |
155 ms |
12432 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |