🌱 DSA (Beginner) · Warmup (Code Confidence) · cozy lesson
Arrays & Strings Warmup
12 min · 1 min read · no scary math, promise
🤖
You’ve got this. Read a little, play a little — I’ll wait. No rush.
def reverse(a):
l, r = 0, len(a)-1
while l < r:
a[l], a[r] = a[r], a[l]
l += 1; r -= 1
def is_pal(s):
s = ''.join(c.lower() for c in s if c.isalnum())
return s == s[::-1]
Do: max, move zeroes, Two Sum brute → map. That’s your base.
💛 Enjoying? Try 5 playful quizzes or watch it move.
Check your understanding
Correct answers earn XP (once each).
1. Reverse in place?
2. Palindrome check?
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