use std::fs::File; use std::io::{BufRead, BufReader}; use std::iter::Iterator; use std::collections::HashMap; struct Point { x: usize, y: usize, } impl Point { fn distance(&self, other: &Point) -> i64 { ((self.x - other.x) as i64).abs() + ((self.y - other.y) as i64).abs() } } impl std::fmt::Display for Point { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "({}, {})", self.x, self.y) } } fn calc_max_area(points: &Vec, min_x: usize, min_y: usize, max_x: usize, max_y: usize) -> (u8, usize) { let distances = calc_distances(points, min_x, min_y, max_x, max_y); let mut areas: HashMap = HashMap::new(); for i in min_x..=max_x { for j in min_y..=max_y { if distances[i][j] == 0 { continue; } areas.entry(distances[i][j]).and_modify(|e| *e += 1).or_insert(1); } } let mut index = 0; let mut max_area = 0; let mut max_area_index = 0; for _point in points.iter() { index += 1; let cur_area = areas.get(&index).unwrap(); if cur_area > &max_area { max_area = *cur_area; max_area_index = index; } } for (key, value) in areas.iter() { println!("{}: {} area {}", key, points.get((index - 1) as usize).unwrap(), value); } (max_area_index, max_area) } fn calc_distances(points: &Vec, min_x: usize, min_y: usize, max_x: usize, max_y: usize) -> [[u8; 500]; 500] { let mut distances = [[0u8; 500]; 500]; for i in min_x..=max_x { for j in min_y..=max_y { let cur_point = Point { x: i, y: j }; let mut min_dis = 500; let mut found_dupe = false; let mut min_index = 0; let mut index = 0; for point in points.iter() { index += 1; let dis = cur_point.distance(point); if dis < min_dis { min_dis = dis; found_dupe = false; min_index = index; } else if dis == min_dis { found_dupe = true; } } if !found_dupe { distances[i][j] = min_index; } } } distances } fn calc_safe_zone(points: &Vec, threshold: i64) -> i64 { let mut area = 0; for i in 0..500 { for j in 0..500 { let point = Point { x: i, y: j }; let distance: i64 = points.iter().map(|p| p.distance(&point)).sum(); if distance < threshold { area += 1; } } } area } fn main() { let points: Vec = BufReader::new(File::open("input").unwrap()) .lines() .map(|line| { let points_str = line.unwrap(); let points_ints: Vec = points_str .as_str() .split(", ") .map(|p| p.parse::().unwrap()) .collect(); Point { x: *points_ints.get(0).unwrap(), y: *points_ints.get(1).unwrap(), } }) .collect(); let mut min_x = 500; let mut min_y = 500; let mut max_x = 0; let mut max_y = 0; for point in points.iter() { if point.x < min_x { min_x = point.x }; if point.x > max_x { max_x = point.x }; if point.y < min_y { min_y = point.y }; if point.y > max_y { max_y = point.y }; } let width = max_x - min_x; let height = max_y - min_y; println!("map size {}x{}", width, height); let (max_area_point, max_area) = calc_max_area(&points, min_x, min_y, max_x, max_y); let max_area_point_index = (max_area_point - 1) as usize; println!("max area point {} {} is {}", max_area_point, points.get(max_area_point_index).unwrap(), max_area); let safe_zone = calc_safe_zone(&points, 10000); println!("safe zone area {}", safe_zone); }