Day 9 - part 2
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					 1 changed files with 42 additions and 58 deletions
				
			
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			@ -1,9 +1,9 @@
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use std::fs;
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const GRID_WIDTH: u32 = 1000;
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const GRID_HEIGHT: u32 = 1000;
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const START_X: u32 = 500;
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const START_Y: u32 = 500;
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const GRID_WIDTH: i32 = 1000;
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const GRID_HEIGHT: i32 = 1000;
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const START_X: i32 = 500;
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const START_Y: i32 = 500;
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pub fn solve() {
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			@ -32,7 +32,7 @@ pub fn solve() {
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            "R" => Dir::Right,
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            _ => Dir::Up
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        };
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        let amount = cmd[1].parse::<u32>().unwrap();
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        let amount = cmd[1].parse::<i32>().unwrap();
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        // move head
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        for _ in 0..amount {
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			@ -62,13 +62,13 @@ enum Dir {
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}
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struct Rope {
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    knots_x: Vec<u32>,
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    knots_y: Vec<u32>,
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    knots_x: Vec<i32>,
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    knots_y: Vec<i32>,
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    tail_visited_grid: Vec<Vec<bool>> // [Y][X]
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}
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impl Rope {
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    pub fn new(knots: u32) -> Self {
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    pub fn new(knots: i32) -> Self {
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        Rope {
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            knots_x: (0..knots).map(|_| START_X).collect(),
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            knots_y: (0..knots).map(|_| START_Y).collect(),
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			@ -102,67 +102,51 @@ impl Rope {
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    fn check_tail_pos(&mut self) {
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        // check pos of each knot except first
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        for i in 1..self.knots_x.len() {
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            // head is too far top/bottom
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            if self.knots_x[i-1].abs_diff(self.knots_x[i]) > 1 {
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                // if necessary, move on Y-axis
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                self.knots_y[i] = self.knots_y[i-1];
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                if self.knots_x[i-1] > self.knots_x[i] { // head below
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                    self.knots_x[i] = self.knots_x[i-1]-1;
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                } else { // head above
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                    self.knots_x[i] = self.knots_x[i-1]+1;
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            if (self.knots_x[i-1] == self.knots_x[i] && (self.knots_y[i-1] - self.knots_y[i]).abs() == 1)
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                    || (self.knots_y[i-1] == self.knots_y[i] && (self.knots_x[i-1] - self.knots_x[i]).abs() == 1) {
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                // Knots are touching, nothing to do
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            } else if (self.knots_x[i-1] - self.knots_x[i]).abs() == 1 && (self.knots_y[i-1] - self.knots_y[i]).abs() == 1 {
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                // Knots are touching diagonally, nothing to do
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            } else {
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                // Tail needs to be moved
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                if self.knots_x[i-1] != self.knots_x[i] && self.knots_y[i-1] != self.knots_y[i] {
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                    // Move diagonally
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                    self.knots_x[i] += normalize(self.knots_x[i-1] - self.knots_x[i]);
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                    self.knots_y[i] += normalize(self.knots_y[i-1] - self.knots_y[i]);
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                } else {
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                    // Move vertically/horizontally
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                    if self.knots_x[i-1] == self.knots_x[i] {
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                        self.knots_y[i] += normalize(self.knots_y[i-1] - self.knots_y[i]);
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                    } else {
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                        self.knots_x[i] += normalize(self.knots_x[i-1] - self.knots_x[i]);
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                    }
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                }
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            // head is too far left/right
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            else if self.knots_y[i-1].abs_diff(self.knots_y[i]) > 1 {
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                // if necessary, move on X-axis
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                self.knots_x[i] = self.knots_x[i-1];
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                if self.knots_y[i-1] > self.knots_y[i] { // head right
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                    self.knots_y[i] = self.knots_y[i-1]-1;
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                } else { // head left
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                    self.knots_y[i] = self.knots_y[i-1]+1;
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                }
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            }
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        }
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        // set current tail (last knot) pos as visited
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        // Set current tail (last knot) pos as visited
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        self.tail_visited_grid[*self.knots_y.last().unwrap() as usize][*self.knots_x.last().unwrap() as usize] = true;        
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        /*
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        let min_x = self.knots_x.iter().min().unwrap();
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        let max_x = self.knots_x.iter().max().unwrap();
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        let min_y = self.knots_y.iter().min().unwrap();
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        let max_y = self.knots_y.iter().max().unwrap();
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        let width = max_x - min_x + 1;
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        let height = max_y - min_y + 1;
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        let mut out: Vec<Vec<String>> = (0..height).map(|_| (0..width).map(|_| ".".to_string()).collect()).collect();
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        for i in (0..self.knots_x.len()).rev() {
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            let x = self.knots_x[i]-min_x;
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            let y = self.knots_y[i]-min_y;
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            out[y as usize][x as usize] = i.to_string();
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        }
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        println!("{}", min_y);
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        out.iter().for_each(|line| {
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            line.iter().for_each(|o| print!("{}",o));
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            println!();
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        });
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        println!();*/
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    }
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    // returns number of cells visited by tail
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    pub fn tail_visited_num(&self) -> u32 {
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    pub fn tail_visited_num(&self) -> i32 {
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        self.tail_visited_grid.iter()
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            .map(|row| 
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                row.iter()
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                .map(|cell| 
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                    if *cell { 1 as u32 } 
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                    else { 0 as u32 }
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                ).sum::<u32>()
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                    if *cell { 1 as i32 } 
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                    else { 0 as i32 }
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                ).sum::<i32>()
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            ).sum()
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    }
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}
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fn normalize(n: i32) -> i32 {
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    if n > 0 {
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        1
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    } else if n < 0 {
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        -1
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    } else {
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        0
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    }
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}
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