feat: 퀵 정렬 구현

Author: ksundong

yoonexample/src/main/java/sort/QuickSort.java

@@ -0,0 +1,38 @@
+package sort;
+
+public class QuickSort implements Sort {
+
+  @Override
+  public void sort(int[] array) {
+    quickSort(array, 0, array.length - 1);
+  }
+
+  private void quickSort(int[] array, int left, int right) {
+    if (left < right) { // 교차되기 전까지
+      int pivot = partition(array, left, right);
+      quickSort(array, left, pivot - 1);
+      quickSort(array, pivot + 1, right);
+    }
+  }
+
+  private int partition(int[] array, int left, int right) {
+    int pivot = array[left];
+    int k = right;
+
+    for (int i = right; i > left; i--) {
+      if (array[i] > pivot) {
+        swap(array, i, k);
+        k--;
+      }
+    }
+
+    swap(array, left, k);
+    return k;
+  }
+
+  private void swap(int[] array, int index1, int index2) {
+    int temp = array[index1];
+    array[index1] = array[index2];
+    array[index2] = temp;
+  }
+}