#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;
const ll mod = 1000007;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie();
cout.tie();
int n;
cin>>n;
vector<ll> dp(n+1,0);
dp[1]=2;
ll broj=2;
vector<ll> v;
ll brojac=0;
for(int i=0;i<n;i++)
{
ll a;
cin>>a;
v.push_back(a);
}
for(int i=2;i<=n;i++)
{
dp[i]=dp[i-1]+broj;
broj++;
dp[i]%=mod;
broj%=mod;
}
for(int i=n-1;i>=1;i--)
{
brojac+=dp[v[i-1]-1];
brojac%=mod;
dp[1]=dp[2];
dp[1]%=mod;
for(int j=2;j<=i;j++)
{
broj=dp[j];
broj%=mod;
dp[j]+=(dp[j-1]+broj);
dp[j]%=mod;
}
}
brojac+=v[n-1];
brojac%=mod;
cout<<brojac<<endl;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
376 KB |
Output is correct |
2 |
Correct |
2 ms |
460 KB |
Output is correct |
3 |
Correct |
2 ms |
664 KB |
Output is correct |
4 |
Correct |
2 ms |
664 KB |
Output is correct |
5 |
Correct |
2 ms |
664 KB |
Output is correct |
6 |
Correct |
2 ms |
672 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
672 KB |
Output is correct |
2 |
Incorrect |
2 ms |
680 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
680 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
680 KB |
Output isn't correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
740 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
3 ms |
740 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
6 ms |
740 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
404 ms |
920 KB |
Output isn't correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
109 ms |
920 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
414 ms |
928 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |