ADDED TWO ARRAY PROGRAMS

Author: VeeruYadav45

Data-Structures/Array/leadersinarray.js

@@ -0,0 +1,48 @@
+/**
+ * [Leaders in an Array](https://www.geeksforgeeks.org/dsa/leaders-in-an-array/)
+ *
+ * A leader in an array is an element that is greater than or equal to
+ * all the elements to its right.
+ *
+ * Example:
+ *   Input:  [16, 17, 4, 3, 5, 2]
+ *   Output: [17, 5, 2]
+ *
+ * Algorithm:
+ * - Start from the rightmost element (which is always a leader).
+ * - Traverse the array from right to left, keeping track of the maximum so far.
+ * - If the current element is greater than or equal to that maximum, it is a leader.
+ * - Reverse the list of leaders at the end to preserve original order.
+ *
+ * @complexity O(n) — each element is visited once.
+ * @flow
+ */
+
+function leaders(arr) {
+    const result = [];
+    const n = arr.length;
+
+    // Start with the rightmost element
+    let maxRight = arr[n - 1];
+
+    // Rightmost element is always a leader
+    result.push(maxRight);
+
+    // Traverse the array from right to left
+    for (let i = n - 2; i >= 0; i--) {
+        if (arr[i] >= maxRight) {
+            maxRight = arr[i];
+            result.push(maxRight);
+        }
+    }
+
+    // Reverse the result array to maintain original order
+    result.reverse();
+
+    return result;
+}
+
+// Driver code
+const arr = [16, 17, 4, 3, 5, 2];
+const result = leaders(arr);
+console.log(result.join(" "));

Data-Structures/Array/test/checkarraysortedornot.js

@@ -0,0 +1,44 @@
+/**
+ * [Check if Array is Sorted](https://www.geeksforgeeks.org/check-if-an-array-is-sorted-in-ascending-order/)
+ *
+ * This function checks whether a given array is sorted in non-decreasing (ascending) order.
+ *
+ * Algorithm:
+ * - Traverse the array from the second element onward.
+ * - Compare each element with its previous one.
+ * - If any element is smaller than its predecessor, the array is not sorted.
+ * - Otherwise, if no such pair exists, the array is sorted.
+ *
+ * Example:
+ *   Input:  [10, 20, 30, 40, 50]
+ *   Output: true
+ *
+ * @param {number[]} arr - The input array of numbers.
+ * @returns {boolean} true if the array is sorted in ascending order, false otherwise.
+ * @complexity O(n) — each element is checked once.
+ * @flow
+ */
+
+function isSorted(arr) {
+    let n = arr.length;
+
+    // Iterate over the array and check if
+    // every element is greater than or equal to previous element.
+    for (let i = 1; i < n; i++) {
+        if (arr[i - 1] > arr[i]) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+// Driver Code
+let arr = [10, 20, 30, 40, 50];
+let n = arr.length;
+
+if (isSorted(arr)) {
+    console.log("true");
+} else {
+    console.log("false");
+}