Data commit

Task/Convex-hull/Rust/convex-hull.rust

@@ -0,0 +1,66 @@
+#[derive(Debug, Clone)]
+struct Point {
+    x: f32,
+    y: f32
+}
+
+fn calculate_convex_hull(points: &Vec<Point>) -> Vec<Point> {
+    //There must be at least 3 points
+    if points.len() < 3 { return points.clone(); }
+
+    let mut hull = vec![];
+
+    //Find the left most point in the polygon
+    let (left_most_idx, _) = points.iter()
+        .enumerate()
+        .min_by(|lhs, rhs| lhs.1.x.partial_cmp(&rhs.1.x).unwrap())
+        .expect("No left most point");
+
+
+    let mut p = left_most_idx;
+    let mut q = 0_usize;
+
+    loop {
+        //The left most point must be part of the hull
+        hull.push(points[p].clone());
+
+        q = (p + 1) % points.len();
+
+        for i in 0..points.len() {
+            if orientation(&points[p], &points[i], &points[q]) == 2 {
+                q = i;
+            }
+        }
+
+        p = q;
+
+        //Break from loop once we reach the first point again
+        if p == left_most_idx { break; }
+    }
+
+    return hull;
+}
+
+//Calculate orientation for 3 points
+//0 -> Straight line
+//1 -> Clockwise
+//2 -> Counterclockwise
+fn orientation(p: &Point, q: &Point, r: &Point) -> usize {
+    let val = (q.y - p.y) * (r.x - q.x) -
+        (q.x - p.x) * (r.y - q.y);
+
+    if val == 0. { return 0 };
+    if val > 0. { return 1; } else { return 2; }
+}
+
+fn main(){
+    let points = vec![pt(16,3), pt(12,17), pt(0,6), pt(-4,-6), pt(16,6), pt(16,-7), pt(16,-3), pt(17,-4), pt(5,19), pt(19,-8), pt(3,16), pt(12,13), pt(3,-4), pt(17,5), pt(-3,15), pt(-3,-9), pt(0,11), pt(-9,-3), pt(-4,-2), pt(12,10)];
+    let hull = calculate_convex_hull(&points);
+
+    hull.iter()
+        .for_each(|pt| println!("{:?}", pt));
+}
+
+fn pt(x: i32, y: i32) -> Point {
+    return Point {x:x as f32, y:y as f32};
+}