Algorithm: two methods (recursion/loop) implement binary search

Algorithm: two methods (recursion/loop) implement binary search

The program is implemented by Golang. The Code is as follows:

1. implement binary search using recursion

 

// Recursive Binary Search func binarySearchTest () {// The binary search array must be sorted nums: = [] int {1, 3, 5, 6, 7, 10, 12, 15, 17, 18, 19, 20, 21} value: = 2var index int = searchIndex (nums, value) fmt. println ("index:", index)} // search for the element value in nums and return indexfunc searchIndex (nums [] int, value int) int {return searchIndexInArea (nums, value, 0, len (nums)-1)} // search for the element value in nums and Return index. where index is located between [left, right] func searchIndexInArea (nums [] int, value int, left int, right int) int {if left> right {return-1} mid: = left + (right-left)/2if nums [mid] <value {return searchIndexInArea (nums, value, mid + 1, right )} else if nums [mid]> value {return searchIndexInArea (nums, value, left, mid-1)} return mid}

2. implement binary search using Loops

 

 

func searchIndex2(nums []int, value int) int {left, right := 0, len(nums)-1for left <= right {mid := left + (right-left)/2if nums[mid] < value {left = mid + 1} else if nums[mid] > value {right = mid - 1} else {return mid}}return -1}