Merge 7e414bf106 into 08b771c863

quick_sort

@@ -0,0 +1,80 @@
+// Quick sort in C++
+
+#include <iostream>
+using namespace std;
+
+// function to swap elements
+void swap(int *a, int *b) {
+  int t = *a;
+  *a = *b;
+  *b = t;
+}
+
+// function to print the array
+void printArray(int array[], int size) {
+  int i;
+  for (i = 0; i < size; i++)
+    cout << array[i] << " ";
+  cout << endl;
+}
+
+// function to rearrange array (find the partition point)
+int partition(int array[], int low, int high) {
+    
+  // select the rightmost element as pivot
+  int pivot = array[high];
+  
+  // pointer for greater element
+  int i = (low - 1);
+
+  // traverse each element of the array
+  // compare them with the pivot
+  for (int j = low; j < high; j++) {
+    if (array[j] <= pivot) {
+        
+      // if element smaller than pivot is found
+      // swap it with the greater element pointed by i
+      i++;
+      
+      // swap element at i with element at j
+      swap(&array[i], &array[j]);
+    }
+  }
+  
+  // swap pivot with the greater element at i
+  swap(&array[i + 1], &array[high]);
+  
+  // return the partition point
+  return (i + 1);
+}
+
+void quickSort(int array[], int low, int high) {
+  if (low < high) {
+      
+    // find the pivot element such that
+    // elements smaller than pivot are on left of pivot
+    // elements greater than pivot are on righ of pivot
+    int pi = partition(array, low, high);
+
+    // recursive call on the left of pivot
+    quickSort(array, low, pi - 1);
+
+    // recursive call on the right of pivot
+    quickSort(array, pi + 1, high);
+  }
+}
+
+// Driver code
+int main() {
+  int data[] = {8, 7, 6, 1, 0, 9, 2};
+  int n = sizeof(data) / sizeof(data[0]);
+  
+  cout << "Unsorted Array: \n";
+  printArray(data, n);
+  
+  // perform quicksort on data
+  quickSort(data, 0, n - 1);
+  
+  cout << "Sorted array in ascending order: \n";
+  printArray(data, n);
+}