Initial commit

cpp/programs/sort_quick.cpp

@@ -0,0 +1,73 @@
+#include <iostream>
+using namespace std;
+
+
+int partition(int arr[], int start, int end) {
+	int pivot = arr[start];
+ 
+	int count = 0;
+	for (int i = start + 1; i <= end; i++) {
+		if (arr[i] <= pivot){
+			count++;
+		}
+	}
+ 
+	// Giving pivot element its correct position
+	int pivotIndex = start + count;
+	swap(arr[pivotIndex], arr[start]);
+ 
+	// Sorting left and right parts of the pivot element
+	int i = start, j = end;
+ 
+	while (i < pivotIndex && j > pivotIndex) {
+		while (arr[i] <= pivot) {
+			// Find index of the first element from left that is higher than pivot
+			i++;
+		}
+ 
+		while (arr[j] > pivot) {
+			// Find index of the first element from right that is lower than pivot
+			j--;
+		}
+ 
+		if (i < pivotIndex && j > pivotIndex) {
+			swap(arr[i], arr[j]);
+			i++;
+			j--;
+		}
+	}
+ 
+	return pivotIndex;
+}
+
+
+void quickSort(int arr[], int low, int high) {
+	if (low < high) {
+		int pi = partition(arr, low, high);
+
+		quickSort(arr, low, pi - 1);
+		quickSort(arr, pi + 1, high);
+	}
+}
+// 4 1 3 5 2
+// 5 1 3 4 2
+// 2 1 3 4 5
+// 1 2 3 4 5
+
+
+
+int main() {
+	int N = 50;
+	int arr[N];
+	for (int i = 0; i < N; i++) {
+		arr[i] = N - i;
+	}
+
+	quickSort(arr, 0, N - 1);
+
+	for (int i = 0; i < N; i++) {
+		cout << arr[i] << " ";
+	}
+	cout << endl;
+	return 0;
+}