Create Counting Sort.cpp

data structures/cpp/Counting Sort.cpp

@@ -0,0 +1,57 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+vector<int> countSort(vector<int>& inputArray)
+{
+    int N = inputArray.size();
+
+    // Finding the maximum element of array inputArray[].
+    int M = 0;
+
+    for (int i = 0; i < N; i++)
+        M = max(M, inputArray[i]);
+
+    // Initializing countArray[] with 0
+    vector<int> countArray(M + 1, 0);
+
+    // Mapping each element of inputArray[] as an index
+    // of countArray[] array
+
+    for (int i = 0; i < N; i++)
+        countArray[inputArray[i]]++;
+
+    // Calculating prefix sum at every index
+    // of array countArray[]
+    for (int i = 1; i <= M; i++)
+        countArray[i] += countArray[i - 1];
+
+    // Creating outputArray[] from countArray[] array
+    vector<int> outputArray(N);
+
+    for (int i = N - 1; i >= 0; i--)
+
+    {
+        outputArray[countArray[inputArray[i]] - 1] = inputArray[i];
+
+        countArray[inputArray[i]]--;
+    }
+
+    return outputArray;
+}
+
+// Driver code
+int main()
+{
+
+    // Input array
+    vector<int> inputArray = { 4, 3, 12, 1, 5, 5, 3, 9 };
+
+    // Output array
+    vector<int> outputArray = countSort(inputArray);
+
+    for (int i = 0; i < inputArray.size(); i++)
+        cout << outputArray[i] << " ";
+
+    return 0;
+}