Minimum Number of Platforms in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read the number of trains.

DSA C

int n;
scanf("%[1]", &n);

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

Ad

Bf

Cs

Dc

Attempts:

3 left

💡 Hint

Common Mistakes

Using %f or %c instead of %d for integer input.

Forgetting the ampersand (&) before the variable.

The format specifier %d is used to read an integer in C.

2fill in blank

medium

Complete the code to sort the arrival times array.

DSA C

qsort(arrival, n, sizeof(int), [1]);

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

Acompare_ints

Bcmpfunc

CcompareInts

Dcompare

Attempts:

3 left

💡 Hint

Common Mistakes

Passing NULL or wrong function name to qsort.

Not defining the comparison function properly.

The comparison function cmpfunc is used with qsort to sort integers.

3fill in blank

hard

Fix the error in the loop condition to find minimum platforms.

DSA C

while (i < n && j [1] n) {
    if (arrival[i] <= departure[j]) {
        platforms++;
        i++;
    } else {
        platforms--;
        j++;
    }
    if (platforms > max_platforms)
        max_platforms = platforms;
}

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

A<=

B>

C<

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using greater than or equal operators causing infinite loops.

Using logical OR instead of AND.

The loop should continue while both i and j are less than n, so the condition is i < n && j < n.

4fill in blank

hard

Fill both blanks to correctly compare arrival and departure times.

DSA C

if (arrival[[1]] <= departure[[2]]) {
    platforms++;
    i++;
} else {
    platforms--;
    j++;
}

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

Ai

Bj

Ck

Dm

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong indices causing incorrect comparisons.

Mixing up arrival and departure indices.

We compare arrival[i] with departure[j] to decide platform count changes.

5fill in blank

hard

Fill all three blanks to initialize variables correctly.

DSA C

int i = [1], j = [2], platforms = [3];

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

A0

B1

Attempts:

3 left

💡 Hint

Common Mistakes

Starting indices at 1 causing out-of-bound errors.

Initializing platforms to 1 instead of 0.

Indices i and j start at 0, and platforms start at 0.