Create mergeSort.js

Data-Structures/Array/mergeSort.js

@@ -0,0 +1,50 @@
+function mergeSort(arr) {
+  if (arr.length <= 1) {
+    return arr; // Base case: array is already sorted
+  }
+
+  // Split the array into two halves
+  const mid = Math.floor(arr.length / 2);
+  const left = arr.slice(0, mid);
+  const right = arr.slice(mid);
+
+  // Recursive calls to mergeSort() for both halves
+  const sortedLeft = mergeSort(left);
+  const sortedRight = mergeSort(right);
+
+  // Merge the sorted halves
+  return merge(sortedLeft, sortedRight);
+}
+
+function merge(left, right) {
+  let mergedArray = [];
+  let leftIndex = 0;
+  let rightIndex = 0;
+
+  // Merge the two sorted arrays
+  while (leftIndex < left.length && rightIndex < right.length) {
+    if (left[leftIndex] <= right[rightIndex]) {
+      mergedArray.push(left[leftIndex]);
+      leftIndex++;
+    } else {
+      mergedArray.push(right[rightIndex]);
+      rightIndex++;
+    }
+  }
+
+  // Append remaining elements from left or right (if any)
+  while (leftIndex < left.length) {
+    mergedArray.push(left[leftIndex]);
+    leftIndex++;
+  }
+
+  while (rightIndex < right.length) {
+    mergedArray.push(right[rightIndex]);
+    rightIndex++;
+  }
+
+  return mergedArray;
+}
+
+// Export the mergeSort() function
+module.exports = mergeSort;