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Golang program for implementation of Interpolation Search

The Interpolation Search is an improvement over Binary Search for instances, where the values in a sorted array are uniformly distributed. Binary Search always goes to middle element to check. On the other hand interpolation search may go to different locations according the value of key being searched. Here is the source code of the Go program to search element in an integer array using Interpolation search algorithm. The output shows the position of element in array.
// Interpolation Search in Golang
package main
import "fmt"

func interpolationSearch(array []int, key int) int {

	min, max := array[0], array[len(array)-1]

	low, high := 0, len(array)-1

	for {
		if key < min {
			return low
		}

		if key > max {
			return high + 1
		}

		// make a guess of the location
		var guess int
		if high == low {
			guess = high
		} else {
			size := high - low
			offset := int(float64(size-1) * (float64(key-min) / float64(max-min)))
			guess = low + offset
		}

		// maybe we found it?
		if array[guess] == key {
			// scan backwards for start of value range
			for guess > 0 && array[guess-1] == key {
				guess--
			}
			return guess
		}

		// if we guessed to high, guess lower or vice versa
		if array[guess] > key {
			high = guess - 1
			max = array[high]
		} else {
			low = guess + 1
			min = array[low]
		}
	}
}


func main(){
	items := []int{1,2, 9, 20, 31, 45, 63, 70, 100}
	fmt.Println(interpolationSearch(items,63))
}
C:\golang\time>go run interpolationsearch.go
6