Merge pull request OpenGenus#3712 from nywleswoey/master

Add pigeonhole sort in Golang

code/sorting/src/pigeonhole_sort/pigeonhole_sort.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+)
+
+// Pigeonhole Sort in Golang
+// Part of Cosmos by OpenGenus Foundation
+
+// PigeonholeSort sorts the given slice
+func PigeonholeSort(a []int) {
+	arrayLength := len(a)
+
+	// this is used to handle for the edge case where there is nothing to sort
+	if arrayLength == 0 {
+		return
+	}
+
+	min := a[0]
+	max := a[0]
+
+	// get the min and max values of the array
+	for _, value := range a {
+		if value < min {
+			min = value
+		}
+
+		if value > max {
+			max = value
+		}
+	}
+
+	size := max - min + 1
+
+	// create the pigeon holes with the initial values
+	holes := make(map[int][]int, size)
+	for i := 0; i < size; i++ {
+		holes[i] = []int{}
+	}
+
+	// for every value in the array, put it in the corresponding pigeonhole
+	for _, value := range a {
+		holes[value-min] = append(holes[value-min], value)
+	}
+
+	// finally, replace the values in the array with the values from each
+	// pigeonhole in order
+	j := 0
+	for i := 0; i < size; i++ {
+		for _, value := range holes[i] {
+			a[j] = value
+			j++
+		}
+	}
+}
+
+func main() {
+	randomSlice := []int{5, 2, 8, 9, 10, 1, 3}
+	fmt.Println("Unsorted Slice: ", randomSlice)
+	PigeonholeSort(randomSlice)
+	// should receive [ 1, 2, 3, 5, 8, 9, 10 ]
+	fmt.Println("Sorted Slice: ", randomSlice)
+}