#[allow(unused_imports)] use std::cmp::*; use std::io::*; #[allow(dead_code)] fn getline() -> String { let mut ret = String::new(); std::io::stdin().read_line(&mut ret).ok(); return ret; } #[allow(dead_code)] fn getword() -> String { let mut stdin = std::io::stdin(); let mut u8b: [u8; 1] = [0]; loop { let mut buf: Vec = Vec::with_capacity(16); loop { let res = stdin.read(&mut u8b); if res.is_err() ||u8b[0] <= ' ' as u8 { break; } else { buf.push(u8b[0]); } } if buf.len() >= 1 { let ret = std::string::String::from_utf8(buf).unwrap(); return ret; } } } #[allow(dead_code)] fn parse(s : &str) -> T { return s.parse::().ok().unwrap(); } const MINF: i32 = -300 * 3000 - 10; fn main() { let n = parse(&getword()); let m: usize = parse(&getword()); let mut w = vec![0; n]; for i in 0 .. n { w[i] = parse(&getword()); } let mut dp: Vec> = vec![vec![[[MINF; 2]; 2]; n + 1]; n + 1]; dp[0][0][0][0] = 0; dp[1][0][0][0] = 0; dp[1][1][1][1] = 0; for i in 2 .. n { dp[i][0][0][0] = 0; for j in 1 .. (n + 1) { for s in 0 .. 2 { for t in 0 .. 2 { dp[i][j][0][t] = max(dp[i][j][0][t], dp[i - 1][j][s][t]); if dp[i - 1][j - 1][s][t] > MINF { dp[i][j][1][t] = max(dp[i][j][1][t], dp[i - 1][j - 1][s][t] + (s as i32) * w[i - 2]); } } } } } dp[n][0][0][0] = 0; for j in 1 .. (n + 1) { for s in 0 .. 2 { for t in 0 .. 2 { dp[n][j][0][t] = max(dp[n][j][0][t], dp[n - 1][j][s][t]); if dp[n - 1][j - 1][s][t] > MINF { dp[n][j][1][t] = max(dp[n][j][1][t], dp[n - 1][j - 1][s][t] + (s as i32) * w[n - 2] + (t as i32) * w[n - 1]); } } } } let mut ma = MINF; for s in 0 .. 2 { for t in 0 .. 2 { ma = max(ma, dp[n][m][s][t]); } } println!("{}", ma); }