Quick sort in java. (#54)

* Quick sort in java.

* fixes

* lint fixes

Sorting/quick-sort/quickSort.java

@@ -0,0 +1,62 @@
+import java.io.*;
+import java.util.*;
+
+public class Quick_Sort {
+  public static void main(String[] args) {
+    int[] arr = takeinput();
+
+    // sort the array
+    Quick_Sort(arr, 0, arr.length - 1);
+
+    // display the array
+    for (int i = 0; i < arr.length; i++)
+      System.out.print(arr[i] + " ");
+  }
+
+  public static int[] takeinput() {
+    Scanner scn = new Scanner(System.in);
+
+    // input array length
+    int n = scn.nextInt();
+
+    int[] arr = new int[n];
+
+    for (int i = 0; i < arr.length; i++) {
+      // input array elements
+      arr[i] = scn.nextInt();
+    }
+
+    return arr;
+  }
+
+  public static void Quick_Sort(int[] arr, int lo, int hi) {
+    // if low index is higher than high index, simply return
+    if (lo >= hi)
+      return;
+
+    // define pivot
+    int pi = (lo + hi) / 2;
+    int pivot = arr[pi];
+    int left = lo, right = hi;
+
+    while (left <= right) {
+      while (arr[left] < pivot)
+        left++;
+
+      while (arr[right] > pivot)
+        right--;
+
+      if (left <= right) {
+        // swap the values
+        int temp = arr[left];
+        arr[left] = arr[right];
+        arr[right] = temp;
+        left++;
+        right--;
+      }
+    }
+
+    Quick_Sort(arr, lo, right);
+    Quick_Sort(arr, left, hi);
+  }
+}