adds countingSort to sorting

sorting/countingSort.go

@@ -0,0 +1,68 @@
+package main
+
+import "fmt"
+
+//use this for strings
+func countingSortString(data []rune, size int) string {
+	length := 256
+	count := make([]int, length)
+	output := make([]rune, size)
+	for i := 0; i < size; i++ {
+		count[data[i]]++
+	}
+
+	for i := 1; i < length; i++ {
+		count[i] += count[i-1]
+	}
+
+	for i := 0; i < size; i++ {
+		output[count[data[i]]-1] = data[i]
+		count[data[i]]--
+	}
+
+	return string(output)
+}
+
+func countingSortNumber(data []int, size int) []int {
+	min := data[0]
+	for _, val := range data {
+		if val < min {
+			min = val
+		}
+	}
+	max := data[0]
+	for _, val := range data {
+		if val > max {
+			max = val
+		}
+	}
+
+	length := max - min + 1
+	count := make([]int, length)
+	output := make([]int, size)
+	for i := 0; i < size; i++ {
+		count[data[i]-min]++
+	}
+
+	for i := 1; i < length; i++ {
+		count[i] += count[i-1]
+	}
+
+	for i := 0; i < size; i++ {
+		output[count[data[i]-min]-1] = data[i]
+		count[data[i]-min]--
+	}
+
+	return output
+
+}
+
+func main() {
+	data := "golang"
+	g := []rune(data)
+	str := countingSortString(g, len(data))
+	fmt.Println(str)
+
+	arr := []int{0, -2, -9, 20, 7}
+	fmt.Println(countingSortNumber(arr, len(arr)))
+}