Next Greater Element Using Stack in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to push elements onto the stack.

DSA C

stack[++top] = [1];

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Atop

Bi

Carr[i]

Dstack[top]

Attempts:

3 left

💡 Hint

Common Mistakes

Pushing the index instead of the element.

Using top instead of arr[i].

We push the current array element arr[i] onto the stack to find its next greater element later.

2fill in blank

medium

Complete the condition to check if the stack is not empty.

DSA C

while (top [1] -1 && stack[top] <= arr[i]) {

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A>

B==

C<

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '>' to check stack emptiness.

Using '<' which is incorrect here.

The stack is not empty if top > -1.

3fill in blank

hard

Fix the error in assigning the next greater element.

DSA C

result[i] = [1];

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Aarr[i]

Bstack[top]

C-1

Dtop

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning arr[i] instead of stack[top].

Assigning -1 incorrectly here.

The next greater element for arr[i] is the top element of the stack.

4fill in blank

hard

Fill both blanks to correctly initialize the stack and result arrays.

DSA C

int stack[[1]], result[[2]];

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An

Btop

Ci

Darr

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'top' or 'i' as array sizes.

Using 'arr' which is not a size.

Both stack and result arrays should be of size n, the number of elements.

5fill in blank

hard

Fill all three blanks to complete the loop that assigns -1 to elements with no next greater element.

DSA C

for ([1] = 0; [2] < [3]; [2]++) {
    result[i] = -1;
}

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

Ai

Bj

Cn

Dtop

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for loop initialization and condition.

Using 'top' instead of 'n' for loop limit.

Use 'i' as the loop variable and 'n' as the limit to assign -1 to all elements without a next greater element.