SDE I - 90 Day DSA Roadmap

Use 90-day pacing in the Plan Builder

1. 1
   Days 1–7

   Baseline and language#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   concept

   Day 1: Refresh Python interview contractsDay 2: Complexity: name the work you are counting
2. 2
   Days 8–28

   Foundations and core repair#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   conceptarrays-hashingtwo-pointersstackbinary-search

   Day 8: Recursion: make each call's contract explicitDay 9: Correctness: explain why the algorithm must workDay 10: Representation: decide what every value meansDay 11: Arrays & HashingDay 12: Two PointersDay 13: StackDay 15: Binary Search
3. 3
   Days 29–49

   Structures and patterns#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   sliding-windowlinked-listtreesheap-priority-queuebacktrackingintervalsgraphsone-d-dp

   Day 29: Sliding WindowDay 30: Linked ListDay 31: TreesDay 32: Heap / Priority QueueDay 33: BacktrackingDay 34: IntervalsDay 36: GraphsDay 37: 1-D Dynamic Programming
4. 4
   Days 50–64

   Variants and selected extensions#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   practiceconcept

   Day 50: Count Signed Target-Sum RangesDay 51: Minimum Ordered Batch CapacityDay 52: Fixed-window signal peaksDay 53: Earliest peak interval overlapDay 54: Earliest finishes in a dependency planDay 55: Nearest declared grid exitDay 57: Integer arithmetic and coordinate reasoning
5. 5
   Days 65–76

   Mixed and confirmed-format practice#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   review

   Day 65: Clarify a changed contract before coding
6. 6
   Days 77–85

   Mocks and targeted recovery#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   mockreview

   Day 78: SDE I - Window Invariant and Changed ConstraintDay 79: Turn one failure into a regression test
7. 7
   Days 86–90

   Consolidation and buffer#

   Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Goals

   • Transfer invariants across core families, compare at least one alternative, and add electives only after prerequisites and scheduled recovery remain feasible.

   Focus

   review

   Day 86: Review and transfer from the mistake logDay 87: Rehearse the final checklist without cramming