[ Cmii ] [ Octopus ] - add some features

agent-go/tmp/test.go

@@ -0,0 +1,51 @@
+package main
+
+import "fmt"
+
+// quic sort s a slice of ints using quicksort algorithm.
+// The function returns nothing. It modifies the slice in place.
+func QuickSort(a []int) { // <-- pass by value, so we can't modify it
+	quick_sort(0, len(a)-1, a)
+}
+
+/*
+ * The following function implements the quicksort algorithm. It requires three parameters:
+ *   left: an index indicating   the left bound of the subarray to be sorted.
+ *   right: an index indicating the right bound of the subarray to be sorted.
+ *   a: the slice of integers to sort. The function modifies the slice in place.
+ */
+func quick_sort(left int, right int, a []int) {
+	if left < right { // only continue if there is more than one element in the subarray
+		pivot := partition(left, right, a)
+		quick_sort(left, pivot-1, a)
+		quick_sort(pivot+1, right, a) // <-- call this function again on the right half of the subarray
+	} else { // if there is only one element in the subarray, we can return immediately
+		return
+	}
+}
+
+func partition(left int, right int, a []int) int {
+	// find a pivot element. This is just one of the examples in the book
+	pivot := a[right]
+
+	// index i will keep track of where to put the pivot element
+	i := left - 1
+
+	// swap the pivot element with a[right]
+	a[right], a[left] = a[left], a[right]
+
+	for j := left; j < right; j++ {
+		if a[j] <= pivot {
+			i += 1 // increment i
+			a[i], a[j] = a[j], a[i]
+		}
+	}
+
+	return i + 1 // put the pivot element at its final position
+}
+
+func main() {
+	arr := []int{2, 45, 36, -78, 90, 1000, -1, 0, -76}
+	QuickSort(arr)
+	fmt.Println("Sorted array:", arr)
+}