Good evening! Here's our prompt for today.

This is a classic interview question that is used in a lot in technical interviews, frequently in the form of a calendar or meeting management application. As such, we'll also assume the same use case, as it's easier to visualize.

Suppose we're given a few arrays, like [1, 4], [2, 5], [7, 10], [12, 16], representing time intervals. The elements within the arrays represent a start time and end time of a meeting. So an array "time range" of [1, 4] would mean that the event starts at 1-o'clock and ends at 4-o'clock.

Now, what if we wanted to merge any overlapping meetings? If one meeting runs into the time of another, we'll want to combine them into one. As such, [1, 4] and [2, 5], who overlap between 4 o'clock and 5 o'clock, would be combined into [1, 5].

For the above example of [1, 4], [2, 5], [7, 10], [12, 16], we would want to return [1, 5], [7, 10], [12, 16]. Can you write a method that will do this?

Constraints

• Size of array ranges <= 100000
• The array will always contain integer values between -1000000000 and 1000000000
• Expected time complexity : O(n)
• Expected space complexity : O(n)

Try to solve this here or in Interactive Mode.

How do I practice this challenge?

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    'PASSED: `mergeIntervals([[1, 4], [2, 5], [7, 10], [12, 16]])` should return `[[1, 5], [7, 10], [12, 16]]`'

var assert = require('assert');

​

function mergeIntervals(ranges) {

  // return ranges

  return result;

}

​

try {

  assertIsFunction(mergeIntervals, '`mergeIntervals` is a function');

​

  console.log('PASSED: ' + '`mergeIntervals` is a function');

} catch (err) {

  console.log(err);

}

​

try {

  assert.deepEqual(

    mergeIntervals([

      [1, 4],

      [2, 5],

      [7, 10],

      [12, 16],

    ]),

    [

      [1, 5],

      [7, 10],

      [12, 16],

    ]

  );

Here's a video of us explaining the solution.

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We'll now take you through what you need to know.

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