feat: add findMajorityElement challange

README.md

@@ -35,6 +35,7 @@ This repository aims to provide a comprehensive collection of algorithms, data s
 - [Find missing numbers](src/challange/array/find-missing-numbers/find-missing-numbers.ts)
 - [Find max subarray](src/challange/array/find-max-subarray/find-max-subarray.ts)
 - [Max profit](src/challange/array/max-profit/max-profit.ts)
+- [Find majority element](src/challange/array/find-majority-element/find-majority-element.ts)
 
 Please note that the repository is still a work in progress, and new algorithms and patterns will be added over time.
 

src/challange/array/find-majority-element/find-majority-element.test.ts

@@ -0,0 +1,16 @@
+import { findMajorityElement } from "./find-majority-element";
+
+describe("findMajorityElement", () => {
+  it("returns the majority element when it exists", () => {
+    expect(findMajorityElement([3, 2, 3])).toBe(3);
+    expect(findMajorityElement([2, 2, 1, 1, 1, 2, 2])).toBe(2);
+  });
+
+  it("handles array with a single element", () => {
+    expect(findMajorityElement([1])).toBe(1);
+  });
+
+  it("handles array with all elements being the same", () => {
+    expect(findMajorityElement([1, 1, 1, 1])).toBe(1);
+  });
+});

src/challange/array/find-majority-element/find-majority-element.ts

@@ -0,0 +1,9 @@
+/**
+ * Given an array of integers, find the majority element in the array.
+ * @param arr - the given array
+ * @returns the majority element if it exists, otherwise undefined;
+ */
+export function findMajorityElement(arr: number[]): number {
+  arr.sort();
+  return arr[Math.floor(arr.length / 2)];
+}