ADDED TWO ARRAY PROGRAMS

Data-Structures/Array/LeadersInArray.js.test

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+import { leaders } from '../leadersinarray.js';
+
+describe('leaders()', () => {
+    test('should return correct leaders for given array', () => {
+        expect(leaders([16, 17, 4, 3, 5, 2])).toEqual([17, 5, 2]);
+    });
+
+    test('should handle a single element array', () => {
+        expect(leaders([10])).toEqual([10]);
+    });
+
+    test('should handle already decreasing array', () => {
+        expect(leaders([10, 9, 8, 7])).toEqual([10, 9, 8, 7]);
+    });
+
+    test('should handle increasing array', () => {
+        expect(leaders([1, 2, 3, 4])).toEqual([4]);
+    });
+
+    test('should handle array with duplicates', () => {
+        expect(leaders([5, 5, 5, 5])).toEqual([5, 5, 5, 5]);
+    });
+});

Data-Structures/Array/leadersinarray.js

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+export function leaders(arr) {
+    const result = [];
+    const n = arr.length;
+    let maxRight = arr[n - 1];
+    result.push(maxRight);
+
+    for (let i = n - 2; i >= 0; i--) {
+        if (arr[i] >= maxRight) {
+            maxRight = arr[i];
+            result.push(maxRight);
+        }
+    }
+
+    result.reverse();
+    return result;
+}

Data-Structures/Array/test/CheckArraySortedOrNot.js.test

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+import { isSorted } from '../checkarraysortedornot.js';
+
+describe('isSorted()', () => {
+    test('should return true for sorted array', () => {
+        expect(isSorted([10, 20, 30, 40, 50])).toBe(true);
+    });
+
+    test('should return false for unsorted array', () => {
+        expect(isSorted([10, 50, 30, 20])).toBe(false);
+    });
+
+    test('should return true for array with equal elements', () => {
+        expect(isSorted([5, 5, 5, 5])).toBe(true);
+    });
+
+    test('should return true for single element array', () => {
+        expect(isSorted([100])).toBe(true);
+    });
+
+    test('should return true for empty array', () => {
+        expect(isSorted([])).toBe(true);
+    });
+});

Data-Structures/Array/test/checkarraysortedornot.js

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+export function isSorted(arr) {
+    const n = arr.length;
+
+    for (let i = 1; i < n; i++) {
+        if (arr[i - 1] > arr[i]) {
+            return false;
+        }
+    }
+    return true;
+}