1use std::{
  2    cmp::Ordering,
  3    ops::{Add, AddAssign, Sub},
  4};
  5
  6#[derive(Clone, Copy, Default, Eq, PartialEq, Debug, Hash)]
  7pub struct Point {
  8    pub row: u32,
  9    pub column: u32,
 10}
 11
 12impl Point {
 13    pub const MAX: Self = Self {
 14        row: u32::MAX,
 15        column: u32::MAX,
 16    };
 17
 18    pub fn new(row: u32, column: u32) -> Self {
 19        Point { row, column }
 20    }
 21
 22    pub fn zero() -> Self {
 23        Point::new(0, 0)
 24    }
 25
 26    pub fn parse_str(s: &str) -> Self {
 27        let mut point = Self::zero();
 28        for (row, line) in s.split('\n').enumerate() {
 29            point.row = row as u32;
 30            point.column = line.len() as u32;
 31        }
 32        point
 33    }
 34
 35    pub fn is_zero(&self) -> bool {
 36        self.row == 0 && self.column == 0
 37    }
 38
 39    pub fn saturating_sub(self, other: Self) -> Self {
 40        if self < other {
 41            Self::zero()
 42        } else {
 43            self - other
 44        }
 45    }
 46}
 47
 48impl<'a> Add<&'a Self> for Point {
 49    type Output = Point;
 50
 51    fn add(self, other: &'a Self) -> Self::Output {
 52        self + *other
 53    }
 54}
 55
 56impl Add for Point {
 57    type Output = Point;
 58
 59    fn add(self, other: Self) -> Self::Output {
 60        if other.row == 0 {
 61            Point::new(self.row, self.column + other.column)
 62        } else {
 63            Point::new(self.row + other.row, other.column)
 64        }
 65    }
 66}
 67
 68impl<'a> Sub<&'a Self> for Point {
 69    type Output = Point;
 70
 71    fn sub(self, other: &'a Self) -> Self::Output {
 72        self - *other
 73    }
 74}
 75
 76impl Sub for Point {
 77    type Output = Point;
 78
 79    fn sub(self, other: Self) -> Self::Output {
 80        debug_assert!(other <= self);
 81
 82        if self.row == other.row {
 83            Point::new(0, self.column - other.column)
 84        } else {
 85            Point::new(self.row - other.row, self.column)
 86        }
 87    }
 88}
 89
 90impl<'a> AddAssign<&'a Self> for Point {
 91    fn add_assign(&mut self, other: &'a Self) {
 92        *self += *other;
 93    }
 94}
 95
 96impl AddAssign<Self> for Point {
 97    fn add_assign(&mut self, other: Self) {
 98        if other.row == 0 {
 99            self.column += other.column;
100        } else {
101            self.row += other.row;
102            self.column = other.column;
103        }
104    }
105}
106
107impl PartialOrd for Point {
108    fn partial_cmp(&self, other: &Point) -> Option<Ordering> {
109        Some(self.cmp(other))
110    }
111}
112
113impl Ord for Point {
114    #[cfg(target_pointer_width = "64")]
115    fn cmp(&self, other: &Point) -> Ordering {
116        let a = (self.row as usize) << 32 | self.column as usize;
117        let b = (other.row as usize) << 32 | other.column as usize;
118        a.cmp(&b)
119    }
120
121    #[cfg(target_pointer_width = "32")]
122    fn cmp(&self, other: &Point) -> Ordering {
123        match self.row.cmp(&other.row) {
124            Ordering::Equal => self.column.cmp(&other.column),
125            comparison @ _ => comparison,
126        }
127    }
128}