struct Scanner { r: R, buf: Vec } impl Scanner { fn new(r: R) -> Scanner { Scanner { r, buf: Vec::with_capacity(8000) } } fn next(&mut self) -> &str { self.buf.clear(); loop { let (done, used) = { let available = self.r.fill_buf().unwrap(); match available.iter().position(|b| !b.is_ascii_whitespace()) { Some(i) => (true, i), None => (false, available.len()), } }; self.r.consume(used); if done || used == 0 { break; } } loop { let (done, used) = { let available = self.r.fill_buf().unwrap(); match available.iter().position(|b| b.is_ascii_whitespace()) { Some(i) => { self.buf.extend_from_slice(&available[..i]); (true, i) } None => { self.buf.extend_from_slice(&available); (false, available.len()) } } }; self.r.consume(used); if done || used == 0 { unsafe { return std::str::from_utf8_unchecked(&self.buf); } } } } } macro_rules! parse { ($s:expr, Chars) => ($s.chars().collect::>()); ($s:expr, Bytes) => ($s.bytes().collect::>()); ($s:expr, Usize1) => (parse!($s, usize) - 1); ($s:expr, $t:ty) => ($s.parse::<$t>().unwrap()); } macro_rules! read { ($sc:expr, [$t:tt; $n:expr]) => ( (0..$n).map(|_| read!($sc, $t)).collect::>() ); ($sc:expr, ($($t:tt),*)) => (($(read!($sc, $t)),*)); ($sc:expr, $t:ident) => (parse!($sc.next(), $t)); ($sc:expr, $($t:tt),*) => (($(read!($sc, $t)),*)); } #[derive(Clone, Copy)] struct ModInt(usize); impl ModInt { const MOD: usize = 1_000_000_007; } impl std::ops::Add for ModInt { type Output = Self; fn add(self, other: Self) -> Self { let x = self.0 + other.0; if x < Self::MOD { Self(x) } else { Self(x - Self::MOD) } } } impl std::ops::AddAssign for ModInt { fn add_assign(&mut self, other: Self) { *self = *self + other; } } impl std::fmt::Display for ModInt { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "{}", self.0) } } fn main() { use std::io::Write; let (stdin, stdout) = (std::io::stdin(), std::io::stdout()); let mut scanner = Scanner::new(stdin.lock()); let mut writer = std::io::BufWriter::new(stdout.lock()); macro_rules! scan { ($($t:tt)*) => (read!(scanner, $($t)*)); } macro_rules! println { ($($arg:tt)*) => (writeln!(writer, $($arg)*).ok()); } let n = scan!(usize); let k = (n as f64).sqrt() as usize; let mut dp = vec![ModInt(0); n + 1]; dp[0] = ModInt(1); let mut sum = vec![vec![ModInt(0); k + 1]; k + 1]; for i in 0..n { let a = scan!(usize); for (j, sum) in sum.iter().enumerate().skip(1) { dp[i] += sum[i % j]; } if i + 1 == n { break; } let val = dp[i]; if a <= k { sum[a][i % a] += dp[i]; } else { for dp in dp[i..n].iter_mut().step_by(a) { *dp += val; } } if a != 1 { dp[i + 1] += val; } } println!("{}", dp[n - 1]); }