add: moveElementToEnd function implementation

Author: EliasAfara

Arrays/MoveElementToEnd.js

@@ -0,0 +1,42 @@
+import { swap } from "./Swap";
+
+/**
+ * Moves all instances of a specified integer to the end of the array.
+ *
+ * @param {number[]} array - The input array of integers.
+ * @param {number} toMove - The integer to be moved to the end.
+ * @returns {number[]} - The modified array with the specified integer at the end.
+ *
+ * @description
+ * Given an array of integers and an integer value, this function mutates the input array
+ * by moving all instances of the specified integer to the end of the array while maintaining
+ * the order of the other integers.
+ *
+ * @complexity
+ * Time complexity:
+ * - Best-case time complexity: O(n) - Occurs when there are no instances of the specified integer in the array, and the function performs a single pass through the array.
+ * - Average-case time complexity: O(n) - In typical scenarios, the function iterates through the array once to move the specified integer to the end.
+ * - Worst-case time complexity: O(n) - Happens when all elements in the array are the specified integer. The function still performs a single pass through the array.
+ * Space complexity: O(1) - Constant space complexity, as the function performs the operation in place.
+ */
+function moveElementToEnd(array, toMove) {
+ let left = 0;
+ let right = array.length - 1;
+
+ while (left < right) {
+ while (left < right && array[right] === toMove) {
+ right--;
+ }
+
+ if (array[left] === toMove) {
+ // Swap the element at 'left' with the element at 'right'
+ swap(array, left, right);
+ }
+
+ left++;
+ }
+
+ return array;
+}
+
+export { moveElementToEnd };

Arrays/tests/MoveElementToEnd.test.js

@@ -0,0 +1,42 @@
+import { moveElementToEnd } from "../MoveElementToEnd";
+
+describe("moveElementToEnd", () => {
+ it("should move all instances of the specified integer to the end (best case)", () => {
+ const array = [1, 2, 3, 4, 5];
+ const toMove = 6;
+ const expectedArray = [1, 2, 3, 4, 5];
+
+ const result = moveElementToEnd(array, toMove);
+
+ expect(result).toEqual(expectedArray);
+ });
+
+ it("should move all instances of the specified integer to the end (average case)", () => {
+ const array = [2, 1, 2, 2, 2, 3, 4, 2];
+ const toMove = 2;
+ const expectedArray = [4, 1, 3, 2, 2, 2, 2, 2];
+
+ const result = moveElementToEnd(array, toMove);
+
+ expect(result).toEqual(expectedArray);
+ });
+
+ it("should move all instances of the specified integer to the end (worst case)", () => {
+ const array = [3, 3, 3, 3, 3];
+ const toMove = 3;
+ const expectedArray = [3, 3, 3, 3, 3];
+
+ const result = moveElementToEnd(array, toMove);
+
+ expect(result).toEqual(expectedArray);
+ });
+
+ it("should handle an empty array", () => {
+ const emptyArray = [];
+ const toMove = 5;
+
+ const result = moveElementToEnd(emptyArray, toMove);
+
+ expect(result).toEqual([]);
+ });
+});