Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource

JavaScript

Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

Behavior

Auto Save

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML

              
                
              
            
!

CSS

              
                
              
            
!

JS

              
                
console.log(missingNumber_2([1]));
console.log(missingNumber_2([0,1]));
console.log(missingNumber_2([9,6,4,2,3,5,7,0,1]));


// ChatGPT
function missingNumber_1(nums) {
  // Create an array of numbers from 0 to the length of `nums`
  let fullRange = Array.from({length: nums.length + 1}, (_, i) => i);
  
  // Find the difference between the two arrays
  let diff = fullRange.filter(x => !nums.includes(x));
  
  // Return the first element of the resulting array
  return diff[0];
}


// ChatGPT
function missingNumber_2(nums) {
  // Sort the input array in ascending order
  nums.sort(); // (a,b) => a-b

  // Get the number of elements in the array
  const count = nums.length;

  // Loop through the elements in the array
  for (let i = 0; i < count; i++) {
    // Check if the current value is not equal to the loop variable "i"
    if (nums[i] !== i) {
      // If not, return "i" as the missing number
      return i;
    }
  }

  // If no missing number is found, return the length of the array
  return count;
}


// ChatGPT
function missingNumber_3(nums) {
  // Get the count of elements in the input array
  const count = nums.length;

  // Create an array with a range of numbers from 0 to count
  const range = Array.from({ length: count+1 }, (_, i) => i);

  // Loop through the elements of the range array
  for (let num of range) {
    // Check if the current number is not in the input array
    if (!nums.includes(num)) {
      // Return the first missing number
      return num;
    }
  }
}



// ChatGPT
function missingNumber_4(nums) {
  // Get the number of elements in the input array
  const count = nums.length;

  // Create an array of numbers from 0 to the count of elements in the input array
  const range = Array.from({ length: count + 1 }, (_, i) => i);

  // Calculate the sum of the range array
  const rangeSum = range.reduce((acc, cur) => acc + cur, 0);

  // Calculate the sum of the input array
  const numsSum = nums.reduce((acc, cur) => acc + cur, 0);

  // Return the difference between the two sums as the missing number
  return rangeSum - numsSum;
}


// ChatGPT
function missingNumber_5(nums) {
  // Create an array of the same size as the input array with all elements set to 0
  const helper = Array.from({ length: nums.length + 1 }, () => 0);

  // Loop through the elements of the input array
  for (const num of nums) {
    // Set the corresponding element in the helper array to 1
    helper[num] = 1;
  }

  // Loop through the elements of the helper array
  for (let i = 0; i < helper.length; i++) {
    // Return the index of the first 0 in the helper array
    if (helper[i] === 0) return i;
  }
}

              
            
!
999px

Console