AtCoder Beginner Contest 303 D

https://atcoder.jp/contests/abc303/tasks/abc303_d

Caps LockがOffとOnの2状態でDPします。

// Shift vs. CapsLock
#![allow(non_snake_case)]

use std::cmp::min;


//////////////////// library ////////////////////

fn read<T: std::str::FromStr>() -> T {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).ok();
    line.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>().split_whitespace()
            .map(|e| e.parse().ok().unwrap()).collect()
}


//////////////////// process ////////////////////

fn read_input() -> (u64, u64, u64, String) {
    let v = read_vec();
    let X = v[0];
    let Y = v[1];
    let Z = v[2];
    let S = read();
    (X, Y, Z, S)
}

fn f(X: u64, Y: u64, Z: u64, S: String) -> u64 {
    let L = S.len();
    let mut v: Vec<(u64, u64)> = (0..L+1).map(|_| (0, 0)).collect();
    for (i, c) in S.chars().enumerate() {
        if c == 'a' {
            let Off = if i == 0 { X } else { min(v[i].0, v[i].1 + Z) + X };
            let On = if i == 0 { Z + Y } else { min(v[i].0 + Z, v[i].1) + Y };
            v[i+1] = (Off, On)
        }
        else {
            let Off = if i == 0 { Y } else { min(v[i].0, v[i].1 + Z) + Y };
            let On = if i == 0 { Z + X } else { min(v[i].0 + Z, v[i].1) + X };
            v[i+1] = (Off, On)
        }
    }
    min(v[L].0, v[L].1)
}


//////////////////// main ////////////////////

fn main() {
    let (X, Y, Z, S) = read_input();
    println!("{}", f(X, Y, Z, S))
}