String Questions at Zomato: What to Expect

String manipulation is a core skill for software engineers at Zomato. With 4 out of 29 total coding questions historically focused on strings, it's a significant area of assessment. This emphasis is practical: Zomato's platform constantly processes text data—restaurant names, dish descriptions, user reviews, search queries, and location parsing. Efficiently handling, validating, and transforming this data is crucial for search relevance, recommendation systems, and user experience. A strong grasp of string algorithms directly translates to building scalable and accurate features.

What to Expect — Types of Problems

The string problems at Zomato typically test fundamental algorithmic patterns applied to real-world scenarios. You can expect:

• String Transformation and Parsing: Tasks like formatting strings (e.g., standardizing phone numbers or addresses), extracting specific substrings, or implementing basic encoders/decoders.
• Pattern Matching and Searching: Problems involving checking for substrings, anagrams, or palindromes, which are foundational for features like search autocomplete or content moderation.
• Validation Problems: Writing logic to validate input strings against rules, such as checking the format of a coupon code, a delivery PIN code, or a user's input for a review.
• Efficient String Operations: Questions that require minimizing time or space complexity when concatenating, comparing, or manipulating large amounts of text data.

These problems are generally of easy to medium difficulty, designed to test your clean coding habits, attention to edge cases (empty strings, special characters), and ability to choose the right in-built functions or data structures.

How to Prepare — Study Tips with One Code Example

Focus on mastering a few key patterns rather than memorizing solutions. Practice using two-pointers for comparisons, hash maps (or objects/dictionaries) for counting characters, and sliding windows for substring problems. Always walk through your logic with sample inputs and edge cases verbally before coding.

A common pattern is using a hash map to compare character frequencies, essential for anagram or permutation problems. Here is an example of checking if two strings are anagrams:

def are_anagrams(s1, s2):
    if len(s1) != len(s2):
        return False
    char_count = {}
    for ch in s1:
        char_count[ch] = char_count.get(ch, 0) + 1
    for ch in s2:
        if ch not in char_count or char_count[ch] == 0:
            return False
        char_count[ch] -= 1
    return True

Recommended Practice Order

Build your skills progressively. Start with basic operations (reversal, palindrome check). Move to problems involving hash maps for counting (anagrams, first unique character). Then, tackle two-pointer techniques (valid palindrome with removal) and sliding window (longest substring without repeating characters). Finally, practice integrated problems that combine these patterns, like parsing and validating a complex string format. Consistently analyze the time and space complexity of your solutions.

Practice String at Zomato