binary-search-list.go

package main

import "fmt"

func main() {
	primes := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}
	p := binarySearch(primes, 59)
	fmt.Println("O número 11 esta na posição ", p)
}

func binarySearch(list []int, item int) int {
	low := 0
	high := len(list) - 1

	for low <= high {
		mid := (low + high) / 2
		guess := list[mid]

		if guess == item {
			return mid
		} else if guess > item {
			high = mid - 1
		} else {
			low = mid + 1
		}
	}
	return 0
}

binary-search.go

package main

import "fmt"

func main() {
	a := binarySearch(253991398, 91)
	fmt.Println("Attempts:", a)
}

func binarySearch(numbers, item int) int {
	high := numbers
	low := 0
	attempts := 0

	for item <= numbers {
		guess := (low + high) / 2

		if item == guess {
			return attempts
		} else if guess > item {
			high = guess - 1
		} else {
			low = guess + 1
		}
		attempts++
	}
	return 0
}

recursive-binary-search-2.go

package main

import "fmt"

var attempts int

func main() {
	primes := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 113, 145, 209, 278, 345, 567, 890, 123455, 12987312}
	binarySearch(primes, 121, 0, len(primes))
}

func binarySearch(l []int, i, low, high int) {
	attempts++
	if high < low {
		fmt.Printf("Could not find %d after %d attempts", i, attempts)
	}
	mid := low + ((high - low) / 2)
	fmt.Println("mid", mid)
	if l[mid] > i {
		binarySearch(l, i, low, mid-1)
	} else if l[mid] < i {
		binarySearch(l, i, mid+1, high)
	} else {
		fmt.Printf("Found %d after %d attempts", mid, attempts)
	}
}

recursive-binary-search.go

package main

import (
	"fmt"
)

var attempts int

func main() {
	primes := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 113, 145, 209, 278, 345, 567, 890, 123455, 12987312}
	binarySearch(primes, 11)
}

func binarySearch(l []int, i int) {
	attempts++
	if len(l) > 1 {
		half := len(l) / 2
		guess := l[half]
		if guess == i {
			fmt.Printf("Found %d after %d attempts", i, attempts)
		} else if guess < i {
			binarySearch(l[half:], i)
		} else if guess > i {
			binarySearch(l[:half], i)
		}
	} else if l[0] == i {
		fmt.Printf("Found %d after %d attempts", l[0], attempts)
	} else {
		fmt.Printf("Could not find %d after %d attempts", i, attempts)
	}
}