Three Sum Problem All Unique Triplets in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to sort the array before processing.

DSA C

qsort(nums, numsSize, sizeof(int), [1]);

Drag options to blanks, or click blank then click option'

Acmpfunc

BcompareInts

CcompareFunc

Dcompare

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong function name for the comparator.

Not passing the comparator function pointer.

The qsort function requires a comparison function pointer. 'cmpfunc' is the standard name used here.

2fill in blank

medium

Complete the code to skip duplicate elements in the outer loop.

DSA C

for (int i = 0; i < numsSize - 2; i++) {
    if (i > 0 && nums[i] == nums[1]) continue;

Drag options to blanks, or click blank then click option'

Ai + 1

Bi - 1

Ci

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with the next element instead of previous.

Not checking i > 0 before accessing i-1.

To skip duplicates, compare current element with the previous one at index i-1.

3fill in blank

hard

Fix the error in the while loop condition to move the left pointer correctly.

DSA C

while (left < right && nums[left] == nums[1]) left++;

Drag options to blanks, or click blank then click option'

Aright

Bleft - 1

Cleft

Dleft + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with left - 1 which is behind the pointer.

Comparing with left itself causing infinite loop.

To skip duplicates, compare nums[left] with nums[left + 1] and then move left forward.

4fill in blank

hard

Fill both blanks to correctly move the right pointer and skip duplicates.

DSA C

while (left < right && nums[right] == nums[1]) [2];

Drag options to blanks, or click blank then click option'

Aright - 1

Bright + 1

Cright--

Dright++

Attempts:

3 left

💡 Hint

Common Mistakes

Using right + 1 which goes out of bounds.

Incrementing right pointer instead of decrementing.

Compare nums[right] with nums[right - 1] and decrement right pointer to skip duplicates.

5fill in blank

hard

Fill all three blanks to correctly add the triplet to the result array.

DSA C

result[*returnSize] = malloc(sizeof(int) * 3);
result[*returnSize][0] = nums[[1]];
result[*returnSize][1] = nums[[2]];
result[*returnSize][2] = nums[[3]];
(*returnSize)++;

Drag options to blanks, or click blank then click option'

Ai

Bleft

Cright

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong indices like k which is undefined here.

Mixing up left and right indices.

The triplet consists of nums[i], nums[left], and nums[right].