Arrays and strings in Python
Problems to practice
- Two Sum
- Best Time to Buy and Sell Stock
- Move Zeroes
- Product of Array Except Self
- Valid Palindrome
- Longest Substring Without Repeating Characters
- Group Anagrams
Example: two sum
def two_sum(nums, target):
seen = {}
for i, num in enumerate(nums):
needed = target - num
if needed in seen:
return [seen[needed], i]
seen[num] = i
return []Time and space complexity
- Time: O(n)
- Space: O(n)
Can you explain it without the notes?
Arrays and strings in Python
Use your own words. Explain an example and one limitation before checking the explanation.
Check your explanation
Common questions
Turn this concept into a clear answer.
Practice this conceptAdapted from 18_DSA_PYTHON.md · “2. Arrays and strings in Python”. Examples are study fragments; framework behavior can depend on your version.