jarVis march (algorithm-archivists#632)

Author: Julian

contents/jarvis_march/code/v/jarvis.v

@@ -0,0 +1,63 @@
+struct Point {
+	x int
+	y int
+}
+
+fn left_most_point(points []Point) Point {
+	mut ret := points[0]
+
+	for p in points {
+		if (p.x < ret.x) || (p.x == ret.x && p.y < ret.y) {
+			ret = p
+		}
+	}
+
+	return ret
+}
+
+fn (p Point) equal(o Point) bool {
+	return p.x == o.x && p.y == o.x
+}
+
+fn counter_clock_wise(p1, p2, p3 Point) bool {
+	return (p3.y-p1.y) * (p2.x-p1.x) >= (p2.y-p1.y) * (p3.x-p1.x)
+}
+
+fn jarvis_march(points []Point) []Point {
+	mut hull_point := left_most_point(points)
+	mut hull_points := [hull_point]
+
+
+	for {
+		mut end_point := points[0]
+
+		for i := 1; i < points.len; i++ {
+			if end_point.equal(points[i]) || !counter_clock_wise(points[i], hull_points[hull_points.len-1], end_point) {
+				end_point = points[i]
+			}
+		}
+
+		hull_point = end_point
+		if end_point.equal(hull_points[0]) {
+			break
+		}
+
+		hull_points << hull_point
+	}
+	return hull_points
+}
+
+fn main() {
+	points := [
+		Point{-5, 2}, Point{5, 7}, Point{-6, -12}, Point{-14, -14}, Point{9, 9},
+		Point{-1, -1}, Point{-10, 11}, Point{-6, 15}, Point{-6, -8}, Point{15, -9},
+		Point{7, -7}, Point{-2, -9}, Point{6, -5}, Point{0, 14}, Point{2, 8}
+	]
+
+	hull_points := jarvis_march(points)
+
+	println('The hull points are:')
+	for p in hull_points {
+		println('x=$p.x y=$p.y')
+	}
+}

contents/jarvis_march/jarvis_march.md

@@ -46,6 +46,8 @@ Since this algorithm, there have been many other algorithms that have advanced t
 [import, lang:"java"](code/java/JarvisMarch.java)
 {% sample lang="go" %}
 [import, lang:"go"](code/golang/jarvis.go)
+{% sample lang="v" %}
+[import, lang:"v"](code/v/jarvis.v)
 {% endmethod %}
 
 <script>