#include <bits/stdc++.h>
using namespace std ;
const int mod = 1000007 ;
int Add(int x , int y)
{
int z = x + y ;
if(z >= mod)
z -= mod ;
return z ;
}
int Mul(int x , int y)
{
return (1ll * x * y) % mod ;
}
const int MAX = 1e4 + 10 ;
int arr[MAX] ;
int n ;
int dp[2][MAX] , val[MAX] ;
int main()
{
ios_base::sync_with_stdio(0) ;
cin.tie(0) ;
cin>>n ;
for(int i = 1 ; i <= n ; ++i)
cin>>arr[i] ;
val[0] = 1 ;
for(int i = 1 ; i <= n ; ++i)
val[i] = max(val[i-1] , arr[i]) ;
for(int j = 1 ; j <= n ; ++j)
dp[(n+1)&1][j] = 1 ;
int ans = 0 ;
for(int i = n ; i >= 1 ; --i)
{
int now = (i&1) ;
int nxt = !now ;
for(int j = 1 ; j <= n ; ++j)
dp[now][j] = Add(Mul(j , dp[nxt][j]) , dp[nxt][j+1]) ;
ans = Add(ans , Mul(arr[i]-1 , dp[nxt][val[i-1]])) ;
}
ans = Add(ans , 1) ;
return cout<<ans<<"\n" , 0 ;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
288 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
2 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
332 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
332 KB |
Output is correct |
2 |
Correct |
5 ms |
332 KB |
Output is correct |
3 |
Correct |
4 ms |
332 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
322 ms |
496 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
103 ms |
404 KB |
Output is correct |
2 |
Correct |
87 ms |
404 KB |
Output is correct |
3 |
Correct |
150 ms |
412 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
361 ms |
476 KB |
Output is correct |
2 |
Correct |
351 ms |
460 KB |
Output is correct |
3 |
Correct |
332 ms |
496 KB |
Output is correct |