use std::cmp::*; // https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { ($($r:tt)*) => { let stdin = std::io::stdin(); let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next = move || -> String{ bytes.by_ref().map(|r|r.unwrap() as char) .skip_while(|c|c.is_whitespace()) .take_while(|c|!c.is_whitespace()) .collect() }; input_inner!{next, $($r)*} }; } macro_rules! input_inner { ($next:expr) => {}; ($next:expr,) => {}; ($next:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($next, $t); input_inner!{$next $($r)*} }; } macro_rules! read_value { ($next:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($next, $t)).collect::>() }; ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error")); } // Segment Tree. This data structure is useful for fast folding on intervals of an array // whose elements are elements of monoid I. Note that constructing this tree requires the identity // element of I and the operation of I. // Verified by: yukicoder No. 2220 (https://yukicoder.me/submissions/841554) struct SegTree { n: usize, orign: usize, dat: Vec, op: BiOp, e: I, } impl SegTree where BiOp: Fn(I, I) -> I, I: Copy { pub fn new(n_: usize, op: BiOp, e: I) -> Self { let mut n = 1; while n < n_ { n *= 2; } // n is a power of 2 SegTree {n: n, orign: n_, dat: vec![e; 2 * n - 1], op: op, e: e} } // ary[k] <- v pub fn update(&mut self, idx: usize, v: I) { debug_assert!(idx < self.orign); let mut k = idx + self.n - 1; self.dat[k] = v; while k > 0 { k = (k - 1) / 2; self.dat[k] = (self.op)(self.dat[2 * k + 1], self.dat[2 * k + 2]); } } // [a, b) (half-inclusive) // http://proc-cpuinfo.fixstars.com/2017/07/optimize-segment-tree/ #[allow(unused)] pub fn query(&self, rng: std::ops::Range) -> I { let (mut a, mut b) = (rng.start, rng.end); debug_assert!(a <= b); debug_assert!(b <= self.orign); let mut left = self.e; let mut right = self.e; a += self.n - 1; b += self.n - 1; while a < b { if (a & 1) == 0 { left = (self.op)(left, self.dat[a]); } if (b & 1) == 0 { right = (self.op)(self.dat[b - 1], right); } a = a / 2; b = (b - 1) / 2; } (self.op)(left, right) } } // https://yukicoder.me/problems/no/2488 (3.5) // \sum A_i から減らす量をどれだけ抑えるかという問題に変換すると、以下の問題を解くことと同値になる。 // A の部分列 C = (c_1 = A_1, ..., c_k = A_N) について、\sum_{1 <= i <= k-1} floor(c_{i+1}/c_i)c_i の最小値を求めよ。 // A_i <= 10^6 なのでこれはセグメント木でできる。計算量は O(10^6 ln (3*10^5) log_2 10^6) 程度。 // (A_i = x として、min seg[xy..xy+x] + xy を seg[x] に chmin する) fn main() { input! { n: usize, a: [usize; n], } const W: usize = 1_000_001; const INF: i64 = 1 << 58; let mut st = SegTree::new(W, min, INF); st.update(a[n - 1], 0); for i in (0..n - 1).rev() { let x = a[i]; let mut me = INF; for y in 1..=(W - 1) / x { let val = st.query(max(x * y, x + 1)..min(x * y + x, W)); me = min(me, val + x as i64 * y as i64); } st.update(x, me); } let mut ans: i64 = a.iter().sum::() as _; ans -= st.query(a[0]..a[0] + 1); println!("{}", ans); }