DSA Simulator
Merge Sort

Merge Sort is a divide-and-conquer algorithm that splits the array into halves, sorts them recursively, and then merges the sorted halves to form the final sorted array.

It has a time complexity of O(n log n) and is much more efficient than Bubble Sort for large datasets.

Example

// Merge Sort in JavaScript
function mergeSort(arr) {
  if (arr.length <= 1) return arr;

  const mid = Math.floor(arr.length / 2);
  const left = mergeSort(arr.slice(0, mid));
  const right = mergeSort(arr.slice(mid));

  return merge(left, right);
}

function merge(left, right) {
  const result = [];
  let i = 0, j = 0;

  while (i < left.length && j < right.length) {
    if (left[i] < right[j]) {
      result.push(left[i++]);
    } else {
      result.push(right[j++]);
    }
  }

  return result.concat(left.slice(i)).concat(right.slice(j));
}

console.log(mergeSort([4, 2, 7, 1, 9, 3])); // Output: [1, 2, 3, 4, 7, 9]
Merge Sort

Build Array

6 elements

Start with an empty array of a chosen length. New slots start as NULL — fill them with Push or Insert below.

Sort

Splits the array recursively, then merges the smaller sorted parts back together.

Tree depth: —Comparisons: 0
Speed
Array Visualizer
6 elements
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1
2
3
4
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20
64
132
95
7
80
Comparing
Just merged
Real-life Use (Merge Sort)

Merge Sort is used in scenarios where large datasets need to be sorted efficiently. It's especially useful in external sorting, where data doesn't fit into memory.

A practical example is sorting millions of search results quickly or processing large log files in cloud services.

Example

// Simulating sorting of large dataset
const logs = [542, 112, 998, 400, 213, 675, 100];
console.log(mergeSort(logs)); // Output: [100, 112, 213, 400, 542, 675, 998]