npm stuff I think

ts/qs.test.ts

@@ -0,0 +1,56 @@
+function qs(arr: number[], lo: number, hi: number): void {
+    if (lo >= hi) {
+        return
+    }
+
+    const pivot_index = partition(arr, lo, hi);
+    qs(arr, lo, pivot_index - 1);
+    qs(arr, pivot_index + 1, hi);
+}
+
+function partition(arr: number[], lo: number, hi: number): number {
+    const pivot = arr[hi];
+    let idx = lo - 1;
+
+    for (let i = lo; i < hi; i++) {
+        if (arr[i] <= pivot) {
+            idx++;
+
+            // if the value of arr[i] is less than or equal to the pivot point value
+            // then switch places with it (placete it in the ith position), at the end of this iteration we will 
+            // hve a weakly sorted array where everything less than the pivot point
+            // will be on the left side of the pivot
+            const tmp = arr[i];
+            arr[i] = arr[idx];
+            arr[idx] = tmp;
+        }
+    }
+
+    // we need to move the pivot value to the where the last point where 
+    // it was larger than value of, so that everything to the left it, is
+    // in fact less then it. 
+    idx++;
+    arr[hi] = arr[idx];
+    arr[idx] = pivot;
+
+    return (idx);
+}
+
+function quick_sort(arr: number[]): void {
+    qs(arr, 0, arr.length - 1);
+}
+
+
+test("quick sort works", () => {
+    let arr = [2, 3, 1, 6, 5, 10, 8, 9];
+    quick_sort(arr);
+    expect(arr).toEqual([1, 2, 3, 5, 6, 8, 9, 10]);
+})
+
+test("quick sort works in worst case possible", () => {
+    let brr = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1];
+    quick_sort(brr);
+    expect(brr).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+
+})
+