From 9cddec9818d2966911061d1f761f5c9dfa0ce610 Mon Sep 17 00:00:00 2001
From: Cole Polyak <colepolyak@gmail.com>
Date: Tue, 22 Oct 2019 13:42:36 +0200
Subject: [PATCH] Added counting sort implemented in Java

---
 sorting/counting_sort/countingSort.java | 44 +++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 sorting/counting_sort/countingSort.java

diff --git a/sorting/counting_sort/countingSort.java b/sorting/counting_sort/countingSort.java
new file mode 100644
index 000000000..509ea34e9
--- /dev/null
+++ b/sorting/counting_sort/countingSort.java
@@ -0,0 +1,44 @@
+public class countingSort{
+	public static void main(String[] args) {
+		int[] unsorted = {0,1,94,1,68,28,8,2,5,8,2,8,2,5,6,6,7,9,9,9,5,2,2,34};
+
+		System.out.println("Array before:");
+		for(int i = 0; i < unsorted.length; i++) System.out.print(unsorted[i] + ", ");
+
+		unsorted = countingSort(unsorted);
+
+		System.out.println("\n\nArray after: ");
+		for(int i = 0; i < unsorted.length; i++) System.out.print(unsorted[i] + ", ");
+
+	}
+
+	public static int[] countingSort(int[] arr) {
+		int[] toReturn = new int[arr.length];
+
+		int min = arr[0];
+		int max = arr[0];
+
+		for(int i = 1; i < arr.length; i++) {
+			if(arr[i] < min) min = arr[i];
+			if(arr[i] > max) max = arr[i];
+		}
+
+		// Where we'll be storing the counts of our values.
+		int[] count = new int[max - min + 1];
+
+		// First loop populating our counts. 
+		for(int i = 0; i < arr.length; i++) count[arr[i] - min]++;
+
+		// Calculating the number of times each value occurs.
+		count[0]--;
+		for(int i = 1; i < count.length; i++) count[i] = count[i] + count[i-1];
+
+		// Determining where we should put the value and how many times it should go there.
+		for(int i = toReturn.length - 1; i >= 0; i--) {
+			int index = count[arr[i] - min]--;
+			toReturn[index] = arr[i];
+		}
+
+		return toReturn;
+	}
+}
\ No newline at end of file