#include <bits/stdc++.h>
using namespace std;
#define FOR(i, j, k) for(int i=(j); i<=(k); i++)
#define FFOR(i, j, k) for(int i=(j); i<(k); i++)
#define DFOR(i, j, k) for(int i=(j); i>=(k); i--)
#define bug(x) cerr<<#x<<" = "<<(x)<<'\n'
#define pb push_back
#define mp make_pair
#define bit(s, i) (((s)>>(i))&1LL)
#define mask(i) ((1LL<<(i)))
#define builtin_popcount __builtin_popcountll
#define __builtin_popcount __builtin_popcountll
using ll=long long; using ld=long double;
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); const ld pi=acos(0)*2;
template <typename T> inline void read(T &x){char c; bool nega=0; while((!isdigit(c=getchar()))&&(c!='-')); if(c=='-'){nega=1; c=getchar();} x=c-48; while(isdigit(c=getchar())) x=x*10+c-48; if(nega) x=-x;}
template <typename T> inline void writep(T x){if(x>9) writep(x/10); putchar(x%10+48);}
template <typename T> inline void write(T x){if(x<0){ putchar('-'); x=-x;} writep(x);}
template <typename T> inline void writeln(T x){write(x); putchar('\n');}
#define taskname "Calvinball"
int n;
const ll base=1000007;
ll f[10002];
ll g[10002];
int main(){
#ifdef Aria
if(fopen(taskname".in", "r"))
freopen(taskname".in", "r", stdin);
#endif // Aria
read(n);
FOR(i, 1, n) f[i]=1;
FOR(i, 1, n){
FOR(j, 0, n) f[j]=(f[j]*j+f[j+1])%base;
g[i]=f[0];
}
int team=0, a;
ll ans=1;
FOR(i, 1, n){
ll oldj=f[0];
FOR(j, 1, n){
ll temp=f[j];
f[j]=(oldj-f[j-1]*(j-1))%base;
oldj=temp;
}
f[0]=g[n-i];
read(a);
ans+=(a-1)*f[team];
team=max(team, a);
}
ans%=base;
if(ans<0) ans+=base;
writeln(ans);
}
//f[i][j] -> have i more people and now have j team
///f[i][j]=f[i-1][j]*j+f[i-1][j+1];
///f[i+1][j]=f[i][j]*j+f[i][j+1];
///f[i+1][j-1]=f[i][j-1]*(j-1)+f[i][j];
///f[i][j]=f[i+1][j-1]-f[i][j-1]*(j-1);
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
2 ms |
256 KB |
Output is correct |
3 |
Correct |
2 ms |
256 KB |
Output is correct |
4 |
Correct |
2 ms |
384 KB |
Output is correct |
5 |
Correct |
4 ms |
384 KB |
Output is correct |
6 |
Correct |
2 ms |
256 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
256 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
356 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
256 KB |
Output is correct |
2 |
Correct |
2 ms |
384 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
412 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
384 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
2 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
384 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
384 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
11 ms |
384 KB |
Output is correct |
2 |
Correct |
11 ms |
384 KB |
Output is correct |
3 |
Correct |
11 ms |
392 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
877 ms |
604 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
250 ms |
444 KB |
Output is correct |
2 |
Correct |
235 ms |
384 KB |
Output is correct |
3 |
Correct |
233 ms |
468 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
915 ms |
544 KB |
Output is correct |
2 |
Correct |
926 ms |
632 KB |
Output is correct |
3 |
Correct |
922 ms |
564 KB |
Output is correct |