Insertion Sort Algorithm in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the outer loop from the second element for insertion sort.

DSA C++

for (int i = [1]; i < n; i++) {
    int key = arr[i];
    int j = i - 1;
    while (j >= 0 && arr[j] > key) {
        arr[j + 1] = arr[j];
        j--;
    }
    arr[j + 1] = key;
}

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An

B1

C2

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Starting the loop at 0 causes unnecessary comparisons.

Starting at 2 skips the second element.

The insertion sort starts from the second element (index 1) because the first element is considered sorted.

2fill in blank

medium

Complete the code to move elements greater than key one position ahead.

DSA C++

while (j >= 0 && arr[j] [1] key) {
    arr[j + 1] = arr[j];
    j--;
}

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A<

B==

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' causes incorrect shifting.

Using '==' does not move elements properly.

We move elements that are greater than the key to the right to make space for the key.

3fill in blank

hard

Fix the error in placing the key after shifting elements.

DSA C++

arr[[1]] = key;

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Aj + 1

Bi

Cj

Di - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using j places key in wrong position.

Using i or i - 1 does not reflect the shifted position.

After shifting, the correct position for the key is at index j + 1.

4fill in blank

hard

Fill both blanks to complete the insertion sort function header and array size parameter.

DSA C++

void insertionSort(int arr[], int [1]) {
    for (int i = 1; i < [2]; i++) {
        int key = arr[i];
        int j = i - 1;
        while (j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = key;
    }
}

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An

Bsize

Clength

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names causes errors.

Using undefined variables in loop condition.

The parameter name for array size is commonly 'n', and the loop uses 'n' to limit iterations.

5fill in blank

hard

Fill all three blanks to print the sorted array after insertion sort.

DSA C++

for (int [1] = 0; [2] < [3]; [1]++) {
    std::cout << arr[[1]] << " ";
}
std::cout << std::endl;

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Ai

Bj

Cn

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for loop control.

Using undefined size variable.

Use 'i' as loop variable, and 'n' as array size to print all elements.