Selection Sort Algorithm in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to swap two elements in the array.

DSA Javascript

let temp = arr[i];
arr[i] = arr[[1]];
arr[[1]] = temp;

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Aj

Bi

Cindex

DminIndex

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping with the wrong index like j or i itself.

Not using a temporary variable for swapping.

We swap the element at position i with the element at position minIndex to place the smallest element at the correct position.

2fill in blank

medium

Complete the code to find the index of the smallest element in the unsorted part of the array.

DSA Javascript

for (let j = i + 1; j < arr.length; j++) {
  if (arr[j] [1] arr[minIndex]) {
    minIndex = j;
  }
}

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A===

B<

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<' which finds the largest element.

Using equality or inequality operators which do not help find the smallest.

We look for the smallest element, so we check if arr[j] is less than arr[minIndex].

3fill in blank

hard

Fix the error in the loop that iterates over the array for selection sort.

DSA Javascript

for (let i = 0; i [1] arr.length - 1; i++) {
  // selection sort logic
}

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A<=

B>

C<

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' causes an extra iteration leading to out-of-bounds errors.

Using '>' or '>=' causes the loop to never run or run incorrectly.

We loop until i is less than arr.length - 1 because the last element will already be sorted.

4fill in blank

hard

Fill both blanks to complete the selection sort inner loop and update the smallest element index.

DSA Javascript

for (let j = [1]; j < arr.length; j++) {
  if (arr[j] [2] arr[minIndex]) {
    minIndex = j;
  }
}

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Ai + 1

Bi

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from i instead of i + 1 includes the already sorted part.

Using '>' instead of '<' finds the largest element.

The inner loop starts from i + 1 to check the unsorted part, and we use '<' to find the smallest element.

5fill in blank

hard

Fill the blanks to create a dictionary mapping elements to their original positions before sorting.

DSA Javascript

let positions = {};
for (let i = 0; i < arr.length; i++) {
  positions[[1]] = [2];
}
// After sorting, positions hold the index of each element
arr.sort((a, b) => a - b);
console.log(positions);

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Aarr[i]

Bi

Carr.length

Di + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using arr.length or i + 1 as keys or values incorrectly.

Mixing keys and values in the dictionary.

We use arr[i] as the key and i as the value to map elements to their original positions. arr.length is unrelated here but included as distractor.