#include <bits/stdc++.h>
using namespace std;
#define MOD 1000007
#define ll long long int
ll dp[10005];
ll dp2[10005];
void calc() {
for(ll i = 1; i <= 10000; i++) {
dp2[i] = (dp[i+1]+dp[i]*i)%MOD;
}
for(int i = 1; i <= 10000; i++) {
dp[i] = dp2[i];
}
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<ll> arr(n);
/*for(int i = 0; i < n; i++) {
arr[i] = 1;
}
int x = 1;
while(arr[0] == 1) {*/
vector<int> cnt(n+1,0);
ll mx = 0;
for(int i = 0; i < n; i++) {
//cout << arr[i] << " ";
dp[i] = 1;
cin >> arr[i];
cnt[arr[i]]++;
mx = max(arr[i],mx);
}
dp[n] = 1;
ll ans = 1;
for(ll i = n-1; i >= 0; i--) {
if(arr[i] > 1) {
// cout << i << " " << arr[i] << " " << dp[arr[i]] << " " << dp[arr[i-1]] << " " << cnt[arr[i]] << endl;
if(cnt[arr[i]] == 1) {
mx--;
}
ans+= ((arr[i]-1)*dp[mx])%MOD;
}
calc();
cnt[arr[i]]--;
}
cout << ans%MOD;
/* cout << x << " " << ans%MOD << "\n";
bool did = false;
for(int i = 0; i < n; i++) {
// cin >> arr[i];
cnt[arr[i]]++;
}
for(int i = n-1; i > 0; i--) {
if(cnt[arr[i]] > 1) {
arr[i]++;
did = true;
for(int j = i+1; j < n; j++) {
arr[j] = 1;
}
break;
}
}
x++;
if(!did) {
break;
}
}*/
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
504 KB |
Output is correct |
2 |
Correct |
2 ms |
504 KB |
Output is correct |
3 |
Correct |
3 ms |
544 KB |
Output is correct |
4 |
Correct |
3 ms |
716 KB |
Output is correct |
5 |
Correct |
3 ms |
716 KB |
Output is correct |
6 |
Correct |
2 ms |
716 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
716 KB |
Output is correct |
2 |
Correct |
3 ms |
716 KB |
Output is correct |
3 |
Correct |
3 ms |
716 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
716 KB |
Output is correct |
2 |
Correct |
2 ms |
724 KB |
Output is correct |
3 |
Correct |
4 ms |
760 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
9 ms |
764 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
764 KB |
Output is correct |
2 |
Correct |
6 ms |
764 KB |
Output is correct |
3 |
Correct |
8 ms |
768 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
19 ms |
772 KB |
Output is correct |
2 |
Correct |
21 ms |
772 KB |
Output is correct |
3 |
Correct |
22 ms |
776 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
37 ms |
836 KB |
Output is correct |
2 |
Correct |
38 ms |
836 KB |
Output is correct |
3 |
Correct |
35 ms |
968 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
361 ms |
996 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
174 ms |
996 KB |
Output is correct |
2 |
Correct |
168 ms |
996 KB |
Output is correct |
3 |
Correct |
187 ms |
1028 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
386 ms |
1084 KB |
Output is correct |
2 |
Correct |
341 ms |
1132 KB |
Output is correct |
3 |
Correct |
373 ms |
1200 KB |
Output is correct |