#define __USE_MINGW_ANSI_STDIO 0
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <algorithm>
#include <queue>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <stack>
#include <deque>
#include <string.h>
#include <sstream>
#include <bitset>
#include <math.h>
#include <assert.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
template <class T>
using ordered_set = __gnu_pbds::tree<T, __gnu_pbds::null_type, less<T>, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>;
template <class T>
using ordered_multiset = __gnu_pbds::tree<T, __gnu_pbds::null_type, less_equal<T>, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>;
#define PI atan2(0, -1)
#define epsilon 1e-9
#define INF 5000000000000000000
#define MOD 1000000007
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
int N, arr [10010], maxi [10010];
long long M = 1000007, dp [2][10010], saves [10010], ret = 1;
int main(){
//freopen("sort.in", "r", stdin); freopen("sort.out", "w", stdout);
ios_base::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(10);
cin >> N; fill(dp[0], dp[0]+N+1, 1); saves[0] = 1;
for(int i = 0; i < N; i++){
cin >> arr[i];
maxi[i+1] = max(maxi[i], arr[i]);
}
for(int i = 1; i <= N; i++){
for(int j = 0; j <= maxi[N-1-i]+2; j++) dp[i%2][j] = (j*dp[(i-1)%2][j]+dp[(i-1)%2][j+1])%M;
saves[i] = dp[i%2][maxi[N-1-i]];
}
for(int i = 0; i < N; i++) ret = (ret+(arr[i]-1)*saves[N-1-i])%M;
cout << ret << '\n';
return 0;
}
/******************************
Kateba ii dake no hanashi darou
Success is only a victory away
- No Game No Life Opening
******************************/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
376 KB |
Output is correct |
2 |
Correct |
2 ms |
376 KB |
Output is correct |
3 |
Correct |
2 ms |
376 KB |
Output is correct |
4 |
Correct |
2 ms |
376 KB |
Output is correct |
5 |
Correct |
2 ms |
376 KB |
Output is correct |
6 |
Correct |
2 ms |
376 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
376 KB |
Output is correct |
2 |
Correct |
2 ms |
376 KB |
Output is correct |
3 |
Correct |
2 ms |
376 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
376 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
500 ms |
776 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
5 ms |
504 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
13 ms |
504 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |