added array-rotation.go

array-rotation.go

@@ -0,0 +1,88 @@
+// ====================================================
+// Data-Structures-with-Go Copyright(C) 2017 Furkan Türkal
+// This program comes with ABSOLUTELY NO WARRANTY; This is free software,
+// and you are welcome to redistribute it under certain conditions; See
+// file LICENSE, which is part of this source code package, for details.
+// ====================================================
+
+/*** INFO
+
+-Write a function rotate(ar[], d, n) that rotates arr[] of size n by d elements
+-1 2 3 4 5 6 7
+
+-Rotation of the above array by 2 will make array
+-3 4 5 6 7 1 2
+
+-METHOD 1 (Use temp array) :
+
+Input arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2, n =7
+1) Store d elements in a temp array
+   temp[] = [1, 2]
+2) Shift rest of the arr[]
+   arr[] = [3, 4, 5, 6, 7, 6, 7]
+3) Store back the d elements
+   arr[] = [3, 4, 5, 6, 7, 1, 2]
+
+-Time complexity O(n)
+-Auxiliary Space: O(d)
+
+
+-METHOD 2 (Rotate one by one) :
+
+leftRotate(arr[], d, n)
+start
+  For i = 0 to i < d
+    Left rotate all elements of arr[] by one
+end
+
+To rotate by one, store arr[0] in a temporary variable temp, move arr[1] to arr[0], arr[2] to arr[1] …and finally temp to arr[n-1]
+Let us take the same example arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2
+Rotate arr[] by one 2 times
+We get [2, 3, 4, 5, 6, 7, 1] after first rotation and [ 3, 4, 5, 6, 7, 1, 2] after second rotation.
+
+-Time complexity: O(n*d)
+-Auxiliary Space: O(1)
+
+***/
+
+package main
+
+import "fmt"
+
+func leftRotate(arr []int, d int, n int){
+	for i := 0; i < d; i++ {
+		leftRotateByOne(arr, n)
+	}
+}
+
+func leftRotateByOne(arr []int, n int){
+	var i, temp int
+	temp = arr[0]
+	for i = 0; i < n - 1; i++ {
+		arr[i] = arr[i + 1]
+	}
+	arr[i] = temp
+}
+
+func printArray(arr []int, size int){
+	if(len(arr) < size){
+		fmt.Println("[ArrayRotation::printArray()] -> Index out of range. Max : ", len(arr))
+		return;
+	}
+	for i := 0; i < size; i++ {
+		fmt.Print(arr[i])
+	}
+}
+
+func main() {
+	arr := []int{1, 2, 3, 4, 5, 6, 7}
+	fmt.Println("-INPUT-")
+	printArray(arr, len(arr) - 1)
+	leftRotate(arr, 2 , 7)
+	fmt.Println()
+	fmt.Println("-OUTPUT-")
+	printArray(arr, 7)
+}
+
+
+