Add Quick Sort Test

Author: LyangHiga

src/sort/quickSort.test.ts

@@ -0,0 +1,61 @@
+import quickSort from "./quickSort";
+
+describe("Test for Quick Sort", () => {
+  const nTimes = 100;
+  const SIZE = 100;
+
+  test("testing if QS sort random array using random pivot", () => {
+    for (let i = 0; i < nTimes; i++) {
+      const arr = Array.from({ length: SIZE }, () =>
+        Math.floor(Math.random() * 1000)
+      );
+      const sortedArr = quickSort(arr);
+      const jsSortedArr = arr.slice().sort((a, b) => a - b);
+      expect(sortedArr[0]).toEqual(jsSortedArr);
+    }
+  });
+
+  test("testing if QS sort random array using first element as pivot", () => {
+    for (let i = 0; i < nTimes; i++) {
+      const arr = Array.from({ length: SIZE }, () =>
+        Math.floor(Math.random() * 1000)
+      );
+      const sortedArr = quickSort(arr, 0, arr.length, 0);
+      const jsSortedArr = arr.slice().sort((a, b) => a - b);
+      expect(sortedArr[0]).toEqual(jsSortedArr);
+    }
+  });
+
+  test("testing if QS sort random array using last element as pivot", () => {
+    for (let i = 0; i < nTimes; i++) {
+      const arr = Array.from({ length: SIZE }, () =>
+        Math.floor(Math.random() * 1000)
+      );
+      const sortedArr = quickSort(arr, 0, arr.length, 1);
+      const jsSortedArr = arr.slice().sort((a, b) => a - b);
+      expect(sortedArr[0]).toEqual(jsSortedArr);
+    }
+  });
+
+  test("testing if QS sort random array using 'median of 3' element as pivot", () => {
+    for (let i = 0; i < nTimes; i++) {
+      const arr = Array.from({ length: SIZE }, () =>
+        Math.floor(Math.random() * 1000)
+      );
+      const sortedArr = quickSort(arr, 0, arr.length, 2);
+      const jsSortedArr = arr.slice().sort((a, b) => a - b);
+      expect(sortedArr[0]).toEqual(jsSortedArr);
+    }
+  });
+
+  test("testing if QS sort random array using 'median of 3 random elements' as pivot", () => {
+    for (let i = 0; i < nTimes; i++) {
+      const arr = Array.from({ length: SIZE }, () =>
+        Math.floor(Math.random() * 1000)
+      );
+      const sortedArr = quickSort(arr, 0, arr.length, 2);
+      const jsSortedArr = arr.slice().sort((a, b) => a - b);
+      expect(sortedArr[0]).toEqual(jsSortedArr);
+    }
+  });
+});

src/sort/quickSort.ts

@@ -122,7 +122,7 @@ const quickSort = (
   right = arr.length,
   chooseP = 3
 ): [number[], number] => {
-  if (right - left < 1) return [arr, 0];
+  if (right - left <= 1) return [arr, 0];
   // to count the number of comparisons
   const comp = right - left - 1;
   let cl, cr;