// IOI 2021
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ends ' '
#define die(x) return cout << x << endl, 0
#define all(v) v.begin(), v.end()
#define sz(x) (int)(x.size())
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) { cerr << ends << H; debug_out(T...); }
#define debug(...) cerr << "{" << #__VA_ARGS__ << "}:", debug_out(__VA_ARGS__)
typedef long long ll;
typedef pair<int, int> pii;
const int INF = 1e9;
const ll MOD = 1e6 + 7;
////////////////////////////////////////////////////////////////////
const int N = 1e4 + 5;
int A[N], MX[N], DP[N];
int main() {
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
mt19937 Rnd(time(0));
int n, ans = 1; cin >> n;
for (int i = 0; i < n; i++) cin >> A[i], MX[i + 1] = max(MX[i], A[i]);
for (int i = 0; i <= n; i++) DP[i] = 1;
for (int i = n - 1; i >= 1; i--) {
ans = (ans + 1LL * (A[i] - 1) * DP[MX[i]] % MOD) % MOD;
for (int j = 1; j <= n; j++) DP[j] = DP[j + 1] + j * DP[j];
}
cout << ans << endl;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
384 KB |
Output is correct |
2 |
Correct |
7 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
384 KB |
Output is correct |
4 |
Correct |
5 ms |
384 KB |
Output is correct |
5 |
Correct |
5 ms |
384 KB |
Output is correct |
6 |
Correct |
5 ms |
384 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
384 KB |
Output is correct |
2 |
Correct |
5 ms |
400 KB |
Output is correct |
3 |
Correct |
5 ms |
384 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
384 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
388 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
5 ms |
384 KB |
Output isn't correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
5 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
7 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
5 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
77 ms |
512 KB |
Output isn't correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
27 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
83 ms |
512 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |