Basic implementation to avoid importing math for abs and absDiff (#147)

Author: spring1843

array/add_two_numbers.go

@@ -22,10 +22,7 @@ func AddTwoNumbers(num1, num2 []int) []int {
 }
 
 func equalizeLengths(num1, num2 []int) ([]int, []int) {
-	diff := len(num2) - len(num1)
-	if diff < 0 { 
-		diff = diff * -1
-	}
+	diff := absDiff(len(num1), len(num2))
 	zeros := make([]int, diff)
 	if len(num2) > len(num1) {
 		num1 = append(zeros, num1...)
@@ -34,3 +31,10 @@ func equalizeLengths(num1, num2 []int) ([]int, []int) {
 	}
 	return num1, num2
 }
+
+func absDiff(a, b int) int {
+	if a > b {
+		return a - b
+	}
+	return b - a
+}

array/find_duplicate_in_array.go

@@ -1,15 +1,20 @@
 package array
 
-import "math"
-
 // FindDuplicate solves the problem in O(n) time and O(1) space.
 func FindDuplicate(list []int) int {
 	for _, item := range list {
-		itemIndex := int(math.Abs(float64(item))) - 1
+		itemIndex := abs(item) - 1
 		if list[itemIndex] < 0 {
 			return item
 		}
 		list[itemIndex] *= -1
 	}
 	return -1
 }
+
+func abs(a int) int {
+	if a < 0 {
+		return -1 * a
+	}
+	return a
+}