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Arrays and Strings: Data Structures and Algorithms: Uncharted

Courses Data Structures and AlgorithmsArrays and Strings

Arrays and Strings

Use indexed storage, in-place movement, and string scans with honest costs.

Data Structures and Algorithms
Unit 2 of 16
20 lessons
128 min
420 XP

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Lessons

20 total

1A Row of BoxesExplain why a known array index gives direct access while finding an unknown value requires a scan.InteractiveConcept6 min20 XPOpen
2Index Is InstantApply direct index access versus scan to contrasting direct access to seat 14C with scanning for it.CodeConcept6 min20 XPOpen
3The Cost of Squeezing InApply right-shift front insertion to inserting at the front of a full lunch line and counting every shift.CodeConcept6 min20 XPOpen
4Append Is Cheap, UsuallyApply capacity-doubling append simulation to appending through occasional capacity doublings.CodeConcept6 min20 XPOpen
5The Amortized BargainExplain how capacity doubling spreads occasional copy costs across many constant-work appends.InteractiveConcept6 min20 XPOpen
6Delete and ShiftApply left-shift indexed deletion to removing an indexed value and tracing what moves left.CodeConcept6 min20 XPOpen
7Swap to the BackApply swap-with-last unordered deletion to removing in constant work when order does not matter.CodeConcept6 min20 XPOpen
8Reverse in PlaceApply two-pointer in-place reversal to moving two pointers inward without a built-in reverse.CodeConcept6 min20 XPOpen
9Rotate the PlaylistApply normalized three-part rotation to rotating tonight’s queue so track four becomes the start.CodeConcept6 min20 XPOpen
10Predict the ArrayTrack array contents and indices accurately through a sequence of reads and mutations.InteractiveConcept6 min20 XPOpen
11Strings Are FrozenApply build-new immutable string update to building a changed string without mutating the source string.CodeConcept6 min20 XPOpen
12Copies Add UpApply collect-parts then join-once construction to collecting string parts and joining once instead of repeatedly copying prefixes.CodeConcept6 min20 XPOpen
13Count the LettersApply paired character-frequency comparison to tallying word-game tiles and comparing anagram inventories.CodeConcept6 min20 XPOpen
14Find the NeedleApply nested substring alignment scan to hand-scanning a text before comparing JavaScript indexOf and Python find.CodeConcept6 min20 XPOpen
15Two-Pointer PalindromeApply two-pointer filtered palindrome scan to checking a phrase while skipping punctuation and spaces.CodePractice8 min20 XPOpen
16Merge the Guest ListsApply two-list zipper merge to zipper-merging two sorted RSVP lists.CodePractice8 min20 XPOpen
17Best Three-Day StreakApply rolling fixed-size window to maintaining a rolling sum over step-count streaks.CodeConcept6 min20 XPOpen
18Grid in a ListApply row-major index arithmetic to flattening theater row and seat coordinates into one numbered row.CodeConcept6 min20 XPOpen
19The Array Price MenuCompare indexed reads, end updates, and ordered insertions by whether they shift existing elements.InteractiveConcept6 min20 XPOpen
20Arrays and Strings Mastery CheckApply in-place array and frequency-map synthesis to combining indexed access, in-place reasoning, and a string scan.CodeMastery check10 min40 XPOpen

Measuring Work Hashing