Streak · 7 days+185 XP
7-Day Data Structure Streak
Spend 15 minutes a day practicing one data structure problem, starting with stacks. Check in once a day.
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Coding · Facts & stats · iChallenge network
The Challenge Stack
Daily facts and stats about stacks in computing, plus real challenges to put them to work.
Warm-up questionNot ranked · tap an answer
Which stack operation looks at the top item without removing it?
Peek (sometimes called top) returns the top item while leaving the stack unchanged.
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Build a Bracket Checker
Write a small program that uses a stack to check whether brackets in a string are balanced. Post a code link or write-up.
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Proof+250 XP
Stack of Plates Demo
Use a stack of books or cups to act out push, pop and peek, then post a short write-up explaining each step.
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Streak · 14 days+220 XP
14-Day Code Journal
Write a few lines each day about something you coded or learned. Check in once a day.
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