new files

Task/Closest-pair-problem/Go/closest-pair-problem-1.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+    "fmt"
+    "math"
+    "math/rand"
+)
+
+type xy struct {
+    x, y float64
+}
+
+const n = 1000
+const scale = 1.
+
+func d(p1, p2 xy) float64 {
+    dx := p2.x - p1.x
+    dy := p2.y - p1.y
+    return math.Sqrt(dx*dx + dy*dy)
+}
+
+func main() {
+    points := make([]xy, n)
+    for i := range points {
+        points[i] = xy{rand.Float64(), rand.Float64() * scale}
+    }
+    p1, p2 := closestPair(points)
+    fmt.Println(p1, p2)
+    fmt.Println("distance:", d(p1, p2))
+}
+
+func closestPair(points []xy) (p1, p2 xy) {
+    if len(points) < 2 {
+        panic("at least two points expected")
+    }
+    min := 2 * scale
+    for i, q1 := range points[:len(points)-1] {
+        for _, q2 := range points[i+1:] {
+            if dq := d(q1, q2); dq < min {
+                p1, p2 = q1, q2
+                min = dq
+            }
+        }
+    }
+    return
+}