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IOI Subtask-First Worksheet

Use when: one problem has visible subtasks, partial-score routes, or several plausible upgrade paths.

Inputs:

  • one statement
  • one score table or subtask breakdown
  • one honest first pass on constraints and edge cases

Output artifact:

  • one filled worksheet that decides the safest next score path instead of leaving it vague

Done when:

  • you can name one bank / upgrade / park decision and justify it with proof + validation, not instinct alone

Fill In This Order

  1. list the visible score buckets or natural checkpoints
  2. write the smallest valid algorithm for each bucket before you think about the full solve
  3. choose one current target and complete the proof gate for only that path
  4. write the exact validation plan before coding
  5. decide the trigger that promotes the next bucket or parks the problem

Main Worksheet

Subtask / score bucket points constraint signature smallest valid algorithm proof state implementation state validation plan submit checkpoint promote / park trigger
1 idea / proved / coded not started / partial / stable
2 idea / proved / coded not started / partial / stable
3 idea / proved / coded not started / partial / stable
4 idea / proved / coded not started / partial / stable

Current Target Proof Gate

Fill only for the score path you are about to trust right now.

Item Your answer
target bucket
state / maintained object
invariant
transition completeness
optimization justification
failure example if false

Validation Box

Check Your answer
smallest legal cases
subtask-boundary cases
brute / checker / grader route
first stop rule

Bank / Upgrade / Park

If this happens... Action
proof gate is clean and validation passed bank the checkpoint
proof is clean but implementation is the bottleneck stabilize, then bank
implementation is stable and one next bucket is clearly adjacent upgrade
proof is still fuzzy or validation keeps moving the target park and protect the safe score

Next Repo Door

Bottleneck Reopen
proof is fuzzy Reasoning
implementation trust is weak Build Kit and Template Library
validation plan is weak Stress Testing Workflow or Local Judge Workflow
topic depth is weak the missed family's corresponding page in Topics and then its Ladder
you need the full timed protocol IOI Checkpoint / Score-Path Drill 01

Pair This With

Research snapshot refreshed against official IOI sources on 2026-04-24.