Two Pointers Questions at Adobe: What to Expect

Two Pointers is a core algorithmic pattern that appears in roughly 16% of Adobe's tagged coding questions. With 36 specific problems, it's a technique you are statistically likely to encounter. Mastering it is non-negotiable for efficient problem-solving in their interviews, as it demonstrates your ability to optimize brute-force solutions and handle array or string data intelligently.

What to Expect — Types of Problems

Adobe's Two Pointers problems generally fall into three categories. First, opposite-direction pointers are used for tasks like finding a pair with a target sum in a sorted array or reversing a string. Second, same-direction (fast & slow) pointers are applied to linked list cycles or removing duplicates in-place. Third, sliding window variants use pointers to maintain a dynamic window for substring or subarray problems, such as finding the longest substring without repeating characters. Expect problems that blend array manipulation with constraints requiring O(n) time and O(1) space, testing both your pattern recognition and implementation precision.

How to Prepare — Study Tips with One Code Example

Focus on understanding the underlying conditions that make a Two Pointer solution viable: typically sorted data or a sequential structure where you can make decisions to move one pointer based on a condition. Start by identifying the brute-force approach, then analyze how two indices can reduce complexity. Practice writing clean, bug-free code without relying on built-in functions that obscure the pointer logic.

A fundamental pattern is the opposite-direction two-pointer search in a sorted array. Below is an example for finding if a pair of numbers sums to a target.

def has_pair_with_sum(arr, target):
    left, right = 0, len(arr) - 1
    while left < right:
        current_sum = arr[left] + arr[right]
        if current_sum == target:
            return True
        elif current_sum < target:
            left += 1
        else:
            right -= 1
    return False

Recommended Practice Order

Build competency progressively. Start with basic opposite-direction problems like "Two Sum II" or "Reverse String." Then, move to same-direction pointers for "Remove Duplicates from Sorted Array." Finally, tackle sliding window problems like "Longest Substring Without Repeating Characters." Within Adobe's list, prioritize high-frequency problems, ensuring you can derive the logic and code each from scratch under time constraints.

Practice Two Pointers at Adobe