#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int mxn = 10004;
const ll mod = 1000007;
int a[mxn];
int n;
ll DP1[mxn];
ll DP2[mxn];
int main(){
cin >> n;
fr(i, 0, n){
cin >> a[i];
}
int mx[n];
int c = 0;
fr(i, 0, n){
c = max(c, a[i]);
mx[i] = c;
}
ll ans = 1;
fr(i, 0, n+1) DP1[i] = 1;
for(int i = n-1; i >= 0; i --){
int nxt = 1;
if(i > 0) nxt = mx[i-1];
ans += ((a[i]-1) * DP1[nxt]) % mod;
ans %= mod;
fr(j, 0, n+1){
DP2[j] = (DP1[j+1] + j*DP1[j]) % mod;
}
fr(j, 0, n+1){
DP1[j] = DP2[j];
}
}
cout<<ans<<endl;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
260 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
232 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
240 KB |
Output is correct |
2 |
Correct |
2 ms |
280 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
212 KB |
Output is correct |
2 |
Correct |
4 ms |
340 KB |
Output is correct |
3 |
Correct |
3 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
259 ms |
512 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
49 ms |
404 KB |
Output is correct |
2 |
Correct |
49 ms |
340 KB |
Output is correct |
3 |
Correct |
49 ms |
444 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
240 ms |
512 KB |
Output is correct |
2 |
Correct |
208 ms |
540 KB |
Output is correct |
3 |
Correct |
207 ms |
560 KB |
Output is correct |