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105 lines
2.9 KiB
Rust
105 lines
2.9 KiB
Rust
advent_of_code::solution!(7);
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pub fn part_one(input: &str) -> Option<usize> {
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let total: usize = input.lines().filter_map(|line| {
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// println!("{line}");
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let m: Vec<&str> = line.split(": ").collect();
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let total = m[0].parse::<usize>().unwrap();
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let values: Vec<usize> = m[1].split(' ').map(|v| v.parse::<usize>().unwrap()).collect();
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// println!("LINE: {} = {:?}", total, values);
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if can_calc(total, &values) { Some(total) } else { None }
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// Some(total)
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}).sum();
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// println!("TOTAL: {}", total);
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Some(total)
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}
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pub fn part_two(input: &str) -> Option<usize> {
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let total: usize = input.lines().filter_map(|line| {
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// println!("{line}");
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let m: Vec<&str> = line.split(": ").collect();
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let total = m[0].parse::<usize>().unwrap();
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let values: Vec<usize> = m[1].split(' ').map(|v| v.parse::<usize>().unwrap()).collect();
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// println!("LINE: {} = {:?}", total, values);
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if can_calc_2(total, &values) { Some(total) } else { None }
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// Some(total)
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}).sum();
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// println!("TOTAL: {}", total);
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Some(total)
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}
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// allowed operators: + and *
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// all possible options OP^(values count - 1)
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// eg 190: 10 19 -- has TWO possible paths, 10 + 19 and 10 * 19
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// eg 123: 4 5 6 3 -- has 8 possible paths; 4+5+6+3, 4+5+6*3, ... 4*5*6*3
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fn can_calc(total: usize, values: &[usize]) -> bool {
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let is_valid = values.iter().fold(vec![0_usize], |subtotals, next_value| {
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process(&subtotals, next_value)
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}).iter().any(|t| *t == total);
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is_valid
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}
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fn process(sum: &[usize], next_value: &usize) -> Vec<usize> {
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sum.iter().flat_map(|v| {
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vec![v + next_value, v * next_value]
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}).collect()
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}
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fn can_calc_2(total: usize, values: &[usize]) -> bool {
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let is_valid = values.iter().fold(vec![0_usize], |subtotals, next_value| {
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process_2(&subtotals, next_value)
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}).iter().any(|t| *t == total);
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is_valid
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}
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fn process_2(sum: &[usize], next_value: &usize) -> Vec<usize> {
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sum.iter().flat_map(|v| {
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let concat_val = (v.to_string() + next_value.to_string().as_str()).parse::<usize>().unwrap();
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vec![v + next_value, v * next_value, concat_val]
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}).collect()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_process() {
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let sum = [1];
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let next_value = 10;
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let result = process(&sum, &next_value);
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assert_eq!(result, vec![11, 10]);
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}
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#[test]
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fn test_can_calc() {
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let values = [1,2,3,4];
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let total = 10;
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let result = can_calc(total, &values);
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assert_eq!(result, true);
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}
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#[test]
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fn test_part_one() {
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let result = part_one(&advent_of_code::template::read_file("examples", DAY));
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assert_eq!(result, Some(3749));
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}
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#[test]
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fn test_part_two() {
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let result: Option<usize> = part_two(&advent_of_code::template::read_file("examples", DAY));
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assert_eq!(result, Some(11387));
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}
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}
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