Walmart technical interviews focus on basic algorithms and optimization thinking. This article demonstrates how to optimize from brute force to optimal solution using the classic Two Sum problem, and shows how oavoservice helps candidates articulate their thoughts.
📋 Problem Description
Given an array of integers nums and a target target, find two integers in the array that sum up to the target value and return their indices.
Constraints:
- Exactly one solution.
- Cannot use the same element twice.
Example:
Input: nums = [2, 7, 11, 15], target = 9
Output: [0, 1]
Explanation: nums[0] + nums[1] = 2 + 7 = 9
🎯 Core Concepts
- Hash Map Application - Space-Time Tradeoff
- Complexity Optimization - O(n²) to O(n)
- Edge Cases - Duplicates and no solution
- Code Quality - Clear naming and comments
💡 Solution Strategy (oavoservice Guidance)
Method 1: Brute Force (Not Recommended)
def twoSum_brute(nums, target):
n = len(nums)
for i in range(n):
for j in range(i + 1, n):
if nums[i] + nums[j] == target:
return [i, j]
return []
Method 2: Hash Map (Optimal)
def twoSum_hash(nums, target):
# val -> index map
num_map = {}
for i, num in enumerate(nums):
complement = target - num
if complement in num_map:
return [num_map[complement], i]
num_map[num] = i
return []
Time Complexity: O(n) Space Complexity: O(n)
📊 Method Comparison
| Method | Time | Space | Pros | Cons |
|---|---|---|---|---|
| Brute Force | O(n²) | O(1) | Simple | Slow |
| Hash Map | O(n) | O(n) | Fast | Extra Space |
| Two Pointers | O(n) | O(1) | Optimal Space | Requires Sorting |
💼 How oavoservice Helps with Walmart Interviews
Thought Guidance - Complete path from brute force to optimization Code Implementation - Ensure clean code Follow-up Prep - Handling variants Time Management - Reasonable allocation
Contact oavoservice for professional VO interview assistance!
Tags: #Walmart #TwoSum #HashMap #Algorithm #VOHelp #InterviewPrep #1point3acres
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