Added Binary Search

This commit is contained in:
luke-else 2021-11-23 23:51:37 +00:00
parent 5c2e7110f8
commit cbfa634e82
2 changed files with 128 additions and 0 deletions

3
BinarySearch/go.mod Normal file
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module PWD
go 1.17

125
BinarySearch/main.go Normal file
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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++
}