ソースコード
#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <algorithm>
#include <complex>
using namespace std;
#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()
typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef vector<VI> VVI;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;
int in() { int x; scanf("%d", &x); return x; }
ll lin() { ll x; scanf("%lld", &x); return x; }
const ll mod = 1e9 + 7;
int main() {
int n;
cin >> n;
VI a(n);
REP(i,n) a[i] = in();
sort(ALL(a));
a.push_back(1e8);
n++;
VL dp(n, 0);
dp[n-1] = 1;
ll s = 1;
FORR(i,n-2,0){
dp[i] = s;
if (a[i] == a[i+1]){
s = (s - dp[i+1] + mod) % mod;
}
s = (s + dp[i]) % mod;
}
cout << dp[0] << endl;
return 0;
}