#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 501;
const ll MOD = (ll)1e9 + 7;
ll A[MAXN],B[MAXN],N;
vector<ll> dp[MAXN],sum[MAXN];
ll get_sum(ll idx,ll i,ll j){
i -= A[idx];
j -= A[idx];
i = max(i,0LL);
if(i > j) return 0;
if(i == 0) return sum[idx][j];
else return sum[idx][j] - sum[idx][i-1];
}
int main(){
cin >> N;
for(int i = 1;i<=N;i++){
cin >> A[i] >> B[i];
for(ll j = A[i];j<=B[i];j++){
dp[i].push_back(0);
sum[i].push_back(0);
}
}
for(ll j = A[N];j<=B[N];j++){
dp[N][j - A[N]] = 1;
sum[N][j - A[N]] = dp[N][j - A[N]];
if(j - A[N] != 0) sum[N][j - A[N]] += sum[N][j - A[N] - 1];
}
for(ll i = N-1;i>=1;i--){
for(ll j = A[i];j<=B[i];j++){
dp[i][j - A[i]] = 1;
for(ll k = i+1;k<=N;k++){
dp[i][j - A[i]] = (dp[i][j - A[i]] + get_sum(k,j+1,B[k])) % MOD;
}
}
for(ll j = A[i];j<=B[i];j++){
sum[i][j - A[i]] = dp[i][j - A[i]];
if(j - A[i] != 0) sum[i][j - A[i]] += sum[i][j - A[i] - 1];
sum[i][j - A[i]] %= MOD;
}
}
ll tot = 0;
for(ll i = 1;i<=N;i++) tot = (tot + sum[i].back()) % MOD;
if(tot < 0) tot += MOD;
cout << tot << endl;
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
376 KB |
Output is correct |
| 2 |
Correct |
4 ms |
488 KB |
Output is correct |
| 3 |
Correct |
4 ms |
488 KB |
Output is correct |
| 4 |
Correct |
3 ms |
648 KB |
Output is correct |
| 5 |
Correct |
3 ms |
648 KB |
Output is correct |
| 6 |
Correct |
4 ms |
648 KB |
Output is correct |
| 7 |
Correct |
3 ms |
648 KB |
Output is correct |
| 8 |
Correct |
4 ms |
648 KB |
Output is correct |
| 9 |
Correct |
3 ms |
648 KB |
Output is correct |
| 10 |
Correct |
3 ms |
648 KB |
Output is correct |
| 11 |
Correct |
3 ms |
648 KB |
Output is correct |
| 12 |
Correct |
3 ms |
648 KB |
Output is correct |
| 13 |
Correct |
3 ms |
648 KB |
Output is correct |
| 14 |
Correct |
4 ms |
648 KB |
Output is correct |
| 15 |
Correct |
3 ms |
648 KB |
Output is correct |
| 16 |
Correct |
3 ms |
648 KB |
Output is correct |
| 17 |
Correct |
4 ms |
648 KB |
Output is correct |
| 18 |
Correct |
3 ms |
648 KB |
Output is correct |
| 19 |
Correct |
3 ms |
648 KB |
Output is correct |
| 20 |
Correct |
3 ms |
648 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
376 KB |
Output is correct |
| 2 |
Correct |
4 ms |
488 KB |
Output is correct |
| 3 |
Correct |
4 ms |
488 KB |
Output is correct |
| 4 |
Correct |
3 ms |
648 KB |
Output is correct |
| 5 |
Correct |
3 ms |
648 KB |
Output is correct |
| 6 |
Correct |
4 ms |
648 KB |
Output is correct |
| 7 |
Correct |
3 ms |
648 KB |
Output is correct |
| 8 |
Correct |
4 ms |
648 KB |
Output is correct |
| 9 |
Correct |
3 ms |
648 KB |
Output is correct |
| 10 |
Correct |
3 ms |
648 KB |
Output is correct |
| 11 |
Correct |
3 ms |
648 KB |
Output is correct |
| 12 |
Correct |
3 ms |
648 KB |
Output is correct |
| 13 |
Correct |
3 ms |
648 KB |
Output is correct |
| 14 |
Correct |
4 ms |
648 KB |
Output is correct |
| 15 |
Correct |
3 ms |
648 KB |
Output is correct |
| 16 |
Correct |
3 ms |
648 KB |
Output is correct |
| 17 |
Correct |
4 ms |
648 KB |
Output is correct |
| 18 |
Correct |
3 ms |
648 KB |
Output is correct |
| 19 |
Correct |
3 ms |
648 KB |
Output is correct |
| 20 |
Correct |
3 ms |
648 KB |
Output is correct |
| 21 |
Execution timed out |
2036 ms |
17908 KB |
Time limit exceeded |
| 22 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
820 ms |
524288 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
376 KB |
Output is correct |
| 2 |
Correct |
4 ms |
488 KB |
Output is correct |
| 3 |
Correct |
4 ms |
488 KB |
Output is correct |
| 4 |
Correct |
3 ms |
648 KB |
Output is correct |
| 5 |
Correct |
3 ms |
648 KB |
Output is correct |
| 6 |
Correct |
4 ms |
648 KB |
Output is correct |
| 7 |
Correct |
3 ms |
648 KB |
Output is correct |
| 8 |
Correct |
4 ms |
648 KB |
Output is correct |
| 9 |
Correct |
3 ms |
648 KB |
Output is correct |
| 10 |
Correct |
3 ms |
648 KB |
Output is correct |
| 11 |
Correct |
3 ms |
648 KB |
Output is correct |
| 12 |
Correct |
3 ms |
648 KB |
Output is correct |
| 13 |
Correct |
3 ms |
648 KB |
Output is correct |
| 14 |
Correct |
4 ms |
648 KB |
Output is correct |
| 15 |
Correct |
3 ms |
648 KB |
Output is correct |
| 16 |
Correct |
3 ms |
648 KB |
Output is correct |
| 17 |
Correct |
4 ms |
648 KB |
Output is correct |
| 18 |
Correct |
3 ms |
648 KB |
Output is correct |
| 19 |
Correct |
3 ms |
648 KB |
Output is correct |
| 20 |
Correct |
3 ms |
648 KB |
Output is correct |
| 21 |
Execution timed out |
2036 ms |
17908 KB |
Time limit exceeded |
| 22 |
Halted |
0 ms |
0 KB |
- |
