Oracle Interview Questions — 100 DSA Problems

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

Most frequently asked Oracle LeetCode questions for software engineering interviews.

• LRU Cache (MEDIUM) — Hash Table, Linked List, Design, Doubly-Linked List
• Number of Islands (MEDIUM) — Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• Two Sum (EASY) — Array, Hash Table
• Longest Substring Without Repeating Characters (MEDIUM) — Hash Table, String, Sliding Window
• Merge Intervals (MEDIUM) — Array, Sorting
• Group Anagrams (MEDIUM) — Array, Hash Table, String, Sorting
• Longest Palindromic Substring (MEDIUM) — Two Pointers, String, Dynamic Programming
• Merge k Sorted Lists (HARD) — Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort
• Sliding Window Maximum (HARD) — Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
• Container With Most Water (MEDIUM) — Array, Two Pointers, Greedy
• Search in Rotated Sorted Array (MEDIUM) — Array, Binary Search
• Binary Tree Right Side View (MEDIUM) — Tree, Depth-First Search, Breadth-First Search, Binary Tree
• Longest Consecutive Sequence (MEDIUM) — Array, Hash Table, Union Find
• Trapping Rain Water (HARD) — Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
• Add Two Numbers (MEDIUM) — Linked List, Math, Recursion
• Spiral Matrix (MEDIUM) — Array, Matrix, Simulation
• Reverse Linked List (EASY) — Linked List, Recursion
• Merge Two Sorted Lists (EASY) — Linked List, Recursion
• Jump Game (MEDIUM) — Array, Dynamic Programming, Greedy
• Best Time to Buy and Sell Stock (EASY) — Array, Dynamic Programming
• Pow(x, n) (MEDIUM) — Math, Recursion
• 3Sum (MEDIUM) — Array, Two Pointers, Sorting
• Course Schedule (MEDIUM) — Depth-First Search, Breadth-First Search, Graph, Topological Sort
• Roman to Integer (EASY) — Hash Table, Math, String
• Binary Tree Zigzag Level Order Traversal (MEDIUM) — Tree, Breadth-First Search, Binary Tree
• Binary Tree Maximum Path Sum (HARD) — Dynamic Programming, Tree, Depth-First Search, Binary Tree
• Search a 2D Matrix II (MEDIUM) — Array, Binary Search, Divide and Conquer, Matrix
• Course Schedule II (MEDIUM) — Depth-First Search, Breadth-First Search, Graph, Topological Sort
• Gas Station (MEDIUM) — Array, Greedy
• Longest Common Prefix (EASY) — String, Trie
• Maximum Subarray (MEDIUM) — Array, Divide and Conquer, Dynamic Programming
• Word Search (MEDIUM) — Array, String, Backtracking, Depth-First Search, Matrix
• First Missing Positive (HARD) — Array, Hash Table
• Kth Largest Element in an Array (MEDIUM) — Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
• Set Matrix Zeroes (MEDIUM) — Array, Hash Table, Matrix
• Lowest Common Ancestor of a Binary Tree (MEDIUM) — Tree, Depth-First Search, Binary Tree
• Min Stack (MEDIUM) — Stack, Design
• Validate Binary Search Tree (MEDIUM) — Tree, Depth-First Search, Binary Search Tree, Binary Tree
• Linked List Cycle (EASY) — Hash Table, Linked List, Two Pointers
• Restore IP Addresses (MEDIUM) — String, Backtracking
• Product of Array Except Self (MEDIUM) — Array, Prefix Sum
• Combination Sum (MEDIUM) — Array, Backtracking
• Valid Anagram (EASY) — Hash Table, String, Sorting
• Sort Colors (MEDIUM) — Array, Two Pointers, Sorting
• Median of Two Sorted Arrays (HARD) — Array, Binary Search, Divide and Conquer
• Zigzag Conversion (MEDIUM) — String
• Delete Node in a Linked List (MEDIUM) — Linked List
• Find First and Last Position of Element in Sorted Array (MEDIUM) — Array, Binary Search
• Generate Parentheses (MEDIUM) — String, Dynamic Programming, Backtracking
• Maximal Square (MEDIUM) — Array, Dynamic Programming, Matrix