Count and Say Problem in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the first term of the count and say sequence.

DSA C

char* countAndSay(int n) {
    if (n == 1) return [1];
    // rest of the code
}

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

A"11"

B"0"

C"1"

D"2"

Attempts:

3 left

💡 Hint

Common Mistakes

Returning "0" instead of "1" as the first term.

Using numeric 1 instead of string "1".

The first term in the count and say sequence is always "1".

2fill in blank

medium

Complete the code to iterate through the previous term string.

DSA C

for (int i = 0; i < strlen(prev); [1]) {
    // process characters
}

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

Ai--

Bi=0

Ci+=2

Di++

Attempts:

3 left

💡 Hint

Common Mistakes

Using i-- which causes infinite loop.

Skipping characters by incrementing by 2.

We increment i by 1 to move through each character in the string.

3fill in blank

hard

Fix the error in the condition to count consecutive characters.

DSA C

while (j < strlen(prev) && prev[j] == [1]) {
    count++;
    j++;
}

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

Aprev[j]

Bprev[i]

Cprev[i+1]

Dprev[j+1]

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing prev[j] with itself causing infinite loop.

Using prev[i+1] which may go out of bounds.

We compare characters at j with the character at i to count repeats.

4fill in blank

hard

Fill both blanks to append count and character to the result string.

DSA C

sprintf(temp, "%d%c", [1], [2]);
strcat(result, temp);

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

Acount

Bprev[i]

Cj

Dcount + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Appending j instead of count.

Appending character at j instead of i.

We append the count and the character at position i to the result.

5fill in blank

hard

Fill all three blanks to update indices and prepare for next iteration.

DSA C

i = [1];
j = [2];
count = [3];

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

Aj

Bi + 1

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Resetting count to 0 causing incorrect counts.

Not updating i and j correctly causing infinite loops.

Set i and j to j to move forward, reset count to 1 for next group.