Minimum cost to set cooking time

Math Enumeration

41.5% acceptance

Feb 25, 2026

236

644

A generic microwave supports cooking times from at least 1 second to at most 99 minutes and 99 seconds. To set cooking time, push at most four digits (padded to 4 with leading zeros). First two digits = minutes, last two = seconds. You have startAt finger position, moveCost per move, pushCost per push. Return the minimum cost to set targetSeconds seconds of cooking time.

Solution

Rust

Time O(n²)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn min_cost_set_time(
    start_at: i32,
    move_cost: i32,
    push_cost: i32,
    target_seconds: i32,
  ) -> i32 {
    let mut best = i32::MAX;
    for m in 0..=99i32 {
      let s = target_seconds - m * 60;
      if s < 0 || s > 99 {
        continue;
      }
      // Encode as number (strip leading zeros)
      let combined = m * 100 + s;
      let digits: Vec<i32> = if combined == 0 {
        vec![0]
      } else {
        let mut d = Vec::new();
        let mut x = combined;
        while x > 0 {
          d.push(x % 10);
          x /= 10;
        }
        d.reverse();
        d
      };
      let mut cost = 0i32;
      let mut prev = start_at;
      for &d in &digits {
        if d != prev {
          cost += move_cost;
        }
        cost += push_cost;
        prev = d;
      }
      best = best.min(cost);
    }
    best
  }
}