#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define llint long long #define inf 1e18 #define rep(x, s, t) for(llint (x) = (s); (x) < (t); (x)++) #define Rep(x, s, t) for(llint (x) = (s); (x) <= (t); (x)++) #define chmin(x, y) (x) = min((x), (y)) #define chmax(x, y) (x) = max((x), (y)) using namespace std; typedef pair P; llint n; llint a[200005]; int main(void) { ios::sync_with_stdio(0); cin.tie(0); cin >> n; for(int i = 1; i <= n; i++) cin >> a[i]; llint cnt = 0; for(int i = n; i >= 1; i--){ if(a[i] > i){ cout << "No" << endl; return 0; } if((a[i]+cnt) % i){ cout << "No" << endl; return 0; } cnt += (a[i]+cnt) / i; } cout << "Yes" << endl; return 0; }