From cbfa634e8228de6995b74de542b6037d12d05489 Mon Sep 17 00:00:00 2001
From: luke-else <52086083+luke-else@users.noreply.github.com>
Date: Tue, 23 Nov 2021 23:51:37 +0000
Subject: [PATCH] Added Binary Search

---
 BinarySearch/go.mod  |   3 ++
 BinarySearch/main.go | 125 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 BinarySearch/go.mod
 create mode 100644 BinarySearch/main.go

diff --git a/BinarySearch/go.mod b/BinarySearch/go.mod
new file mode 100644
index 0000000..e938e2e
--- /dev/null
+++ b/BinarySearch/go.mod
@@ -0,0 +1,3 @@
+module PWD
+
+go 1.17
diff --git a/BinarySearch/main.go b/BinarySearch/main.go
new file mode 100644
index 0000000..d7fd2d3
--- /dev/null
+++ b/BinarySearch/main.go
@@ -0,0 +1,125 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"time"
+)
+
+func main() {
+	//list := []int{1, 2, 3, 4, 5, 6, 7}
+
+	//x := RecursiveBinarySearch(list, getVal(), 0, len(list)-1)
+
+	//fmt.Println(x)
+
+	testTimed(10000000)
+}
+
+func RecursiveBinarySearch(list []int, value int, start int, end int) int {
+	var mid int = (start + end) / 2
+
+	if start == (end - 1) {
+		if list[mid] == value {
+			return mid
+		}
+		return -1
+	}
+
+	if value < list[mid] {
+		return RecursiveBinarySearch(list, value, start, mid)
+	}
+	return RecursiveBinarySearch(list, value, mid, end)
+
+}
+
+func getVal() (value int) {
+
+	var input string
+
+	fmt.Println("What value would you like to find in the list:")
+	fmt.Scan(&input)
+
+	value, err := strconv.Atoi(input)
+
+	if err != nil {
+		fmt.Println("Invalid Input")
+		return getVal()
+	}
+
+	return
+}
+
+func generateList(value int) (list []int) {
+
+	for i := 1; i <= value; i++ {
+		list = append(list, i)
+	}
+	return
+}
+
+func generateRandomList(value int) (list []int) {
+	for i := 1; i <= value; i++ {
+		list = append(list, rand.Intn(value))
+	}
+	return
+}
+
+func testTimed(value int) {
+
+	const mult int = 1000000
+
+	for i := 1; i <= value; i++ {
+
+		start := time.Now()
+
+		list := generateRandomList(i * mult)
+		list = mergeSort(list, 0, len(list)-1)
+
+		rnd := rand.Intn(i*mult) + 1
+
+		x := RecursiveBinarySearch(list, rnd, 0, len(list)-1)
+
+		//fmt.Println(time.Now().Sub(start), x, i*1000, "items")
+		fmt.Println("found number ", rnd, ":", x, " in a list of ", len(list), " items in ", time.Since(start))
+	}
+}
+
+func mergeSort(nums []int, start int, end int) []int {
+	if start == end {
+		return []int{nums[start]}
+	}
+
+	var mid int = ((end - start) / 2) + start
+
+	//Assign values back into Left and right
+	left := mergeSort(nums, start, mid)
+	right := mergeSort(nums, mid+1, end)
+
+	var combined []int
+
+	//Pointers for new array
+	leftPointer, rightPointer := 0, 0
+
+	for leftPointer <= len(left)-1 || rightPointer <= len(right)-1 {
+
+		if leftPointer == len(left) {
+			addValue(&combined, right[rightPointer], &rightPointer)
+		} else if rightPointer == len(right) {
+			addValue(&combined, left[leftPointer], &leftPointer)
+		} else {
+			if left[leftPointer] <= right[rightPointer] {
+				addValue(&combined, left[leftPointer], &leftPointer)
+			} else {
+				addValue(&combined, right[rightPointer], &rightPointer)
+			}
+		}
+	}
+	return combined
+}
+
+func addValue(nums *[]int, value int, pointer *int) {
+	*nums = append(*nums, value)
+	*pointer++
+}