start work on day 5

2021/src/day5.rs

@@ -0,0 +1,77 @@
+use color_eyre::eyre;
+use num::{Integer, integer::gcd};
+
+
+#[derive(Copy, Clone)]
+struct Point {
+    x: isize,
+    y: isize,
+}
+
+
+#[derive(Copy, Clone)]
+struct Line {
+    start: Point,
+    end: Point,
+}
+
+
+#[derive(Copy, Clone)]
+struct Slope {
+    rise: isize,
+    run: isize,
+}
+
+
+impl Line {
+    fn slope(&self) -> Slope {
+        let mut rise = self.end.y - self.start.y;
+        let mut run = self.end.x - self.start.x;
+        if rise != 0 && run != 0 {
+            let divisor = gcd(rise, run);
+            rise /= divisor;
+            run /= divisor;
+        }
+        Slope {rise, run}
+    }
+}
+
+
+struct PointsIter<'a> {
+    line: &'a Line,
+    pos: Point,
+    slope: Slope,
+}
+
+impl PointsIter<'_> {
+    fn from(line: &Line) -> Self {
+        PointsIter {
+            line,
+            pos: line.start,
+            slope: line.slope(),
+        }
+    }
+}
+
+impl Iterator for PointsIter {
+    type Item = Point;
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos.x = self.line.start.x && self.pos.y == self.line.start.y {
+            return Some(self.pos);
+        }
+
+        if self.pos.x != self.line.end.x && self.pos.y != self.line.end.y {
+            self.pos.y += self.slope.rise;
+            self.pos.x += self.slope.run;
+            return Some(self.pos);
+        }
+        else {
+            return None;
+        }
+    }
+}
+
+
+struct GridCounter<const W: usize, const H: usize> {
+    rows: [[usize; W]; H],
+}