ServiceNow Interview Questions — 84 DSA Problems

80 problems with full solutions in Python, Java, C++, JavaScript, Go, Rust.

Most frequently asked ServiceNow LeetCode questions for software engineering interviews.

• Trapping Rain Water (HARD) — Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
• Subarray Product Less Than K (MEDIUM) — Array, Binary Search, Sliding Window, Prefix Sum
• Valid Parentheses (EASY) — String, Stack
• Group Anagrams (MEDIUM) — Array, Hash Table, String, Sorting
• LRU Cache (MEDIUM) — Hash Table, Linked List, Design, Doubly-Linked List
• Lexicographically Smallest String After Operations With Constraint (MEDIUM) — String, Greedy
• Generate Parentheses (MEDIUM) — String, Dynamic Programming, Backtracking
• Number of Distinct Roll Sequences (HARD) — Dynamic Programming, Memoization
• Find Minimum Diameter After Merging Two Trees (HARD) — Tree, Depth-First Search, Breadth-First Search, Graph
• Longest Substring Without Repeating Characters (MEDIUM) — Hash Table, String, Sliding Window
• Best Time to Buy and Sell Stock (EASY) — Array, Dynamic Programming
• Move Zeroes (EASY) — Array, Two Pointers
• Zigzag Conversion (MEDIUM) — String
• Design HashMap (EASY) — Array, Hash Table, Linked List, Design, Hash Function
• Merge Intervals (MEDIUM) — Array, Sorting
• Daily Temperatures (MEDIUM) — Array, Stack, Monotonic Stack
• Maximal Square (MEDIUM) — Array, Dynamic Programming, Matrix
• Kth Largest Element in an Array (MEDIUM) — Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
• Two Sum (EASY) — Array, Hash Table
• Container With Most Water (MEDIUM) — Array, Two Pointers, Greedy
• First Missing Positive (HARD) — Array, Hash Table
• Number of Islands (MEDIUM) — Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• Longest Palindromic Substring (MEDIUM) — Two Pointers, String, Dynamic Programming
• Median of Two Sorted Arrays (HARD) — Array, Binary Search, Divide and Conquer
• Search in Rotated Sorted Array (MEDIUM) — Array, Binary Search
• Pacific Atlantic Water Flow (MEDIUM) — Array, Depth-First Search, Breadth-First Search, Matrix
• Top K Frequent Words (MEDIUM) — Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
• Reverse Linked List (EASY) — Linked List, Recursion
• LFU Cache (HARD) — Hash Table, Linked List, Design, Doubly-Linked List
• Maximum Product Subarray (MEDIUM) — Array, Dynamic Programming
• Validate Binary Search Tree (MEDIUM) — Tree, Depth-First Search, Binary Search Tree, Binary Tree
• String Compression (MEDIUM) — Two Pointers, String
• Set Matrix Zeroes (MEDIUM) — Array, Hash Table, Matrix
• Number of Visible People in a Queue (HARD) — Array, Stack, Monotonic Stack
• Validate IP Address (MEDIUM) — String
• First Unique Character in a String (EASY) — Hash Table, String, Queue, Counting
• Number of Distinct Substrings in a String (MEDIUM) — String, Trie, Rolling Hash, Suffix Array, Hash Function
• Binary Tree Right Side View (MEDIUM) — Tree, Depth-First Search, Breadth-First Search, Binary Tree
• Longest Consecutive Sequence (MEDIUM) — Array, Hash Table, Union Find
• Asteroid Collision (MEDIUM) — Array, Stack, Simulation
• Sum Root to Leaf Numbers (MEDIUM) — Tree, Depth-First Search, Binary Tree
• Fraction to Recurring Decimal (MEDIUM) — Hash Table, Math, String
• Vowels of All Substrings (MEDIUM) — Math, String, Dynamic Programming, Combinatorics
• Meeting Rooms II (MEDIUM) — Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
• Reverse Words in a String II (MEDIUM) — Two Pointers, String
• Maximum Subarray (MEDIUM) — Array, Divide and Conquer, Dynamic Programming
• Largest Number (MEDIUM) — Array, String, Greedy, Sorting
• Valid Parenthesis String (MEDIUM) — String, Dynamic Programming, Stack, Greedy
• House Robber (MEDIUM) — Array, Dynamic Programming
• Letter Combinations of a Phone Number (MEDIUM) — Hash Table, String, Backtracking