From b17b4cbb39019ec783981e95e4720cf4ae8e0c98 Mon Sep 17 00:00:00 2001
From: dwij2812 <dwijhariket@gmail.com>
Date: Fri, 25 Sep 2020 16:06:32 +0530
Subject: [PATCH] Added Interpolation Search

---
 README.md                        |  1 +
 searching/interpolationSearch.go | 65 ++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 searching/interpolationSearch.go

diff --git a/README.md b/README.md
index a261c2d..a2cd36b 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,7 @@ Algorithms
   * [binary search](https://en.wikipedia.org/wiki/Binary_search_algorithm)
   * [linear search](https://en.wikipedia.org/wiki/Linear_search)
   * [jump search](https://en.wikipedia.org/wiki/Jump_search)
+  * [interpolation search](https://en.wikipedia.org/wiki/Interpolation_search)
 
 #### Collections
 
diff --git a/searching/interpolationSearch.go b/searching/interpolationSearch.go
new file mode 100644
index 0000000..9ff4ed9
--- /dev/null
+++ b/searching/interpolationSearch.go
@@ -0,0 +1,65 @@
+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() {
+	searchValue := 0
+
+	arr := []int{1, 5, 100, 0, -100, 15, 4, 102, 30, 1000}
+	fmt.Println(arr)
+
+	var index = InterpolationSearch(arr, searchValue)
+
+	if index < 0 {
+		fmt.Println("Not found")
+		return
+	} else {
+		fmt.Println("Found at position: ", index)
+		return
+	}
+}