/ DSA with C++ / Phase 25 Phase 25 Days 141-146
Competitive Programming Craft & Contest Mastery Turn technique into rating: constructive, game theory, interactive, and a real contest routine
Phase Goal Build a sustainable contest and upsolving routine; distinguish CodeChef stars from Codeforces titles and measure progress without promising a rating.
Day 141: Game theory
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Day 142: Constructive algorithms
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Day 143: Interactive & randomized problems
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Day 144: Ad-hoc, math & observation problems
Observation-first problems
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Day 145: Contest strategy & a sustainable rating practice
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Day 146: Capstone — a self-run contest simulation
Build your permanent toolkit
Practice, delayed recall, and independent transfer Choose one core problem from LeetCode, Codeforces, AtCoder, or CSES after checking its prerequisites; hide its technique label Spend 10–20 minutes retrieving one earlier mechanism and one earlier bug before new work; prioritize weak prerequisites Use a five-task bank: guided warm-up, core, changed constraint, delayed recall, optional stretch; attempt one or two, not all five on a timer Before a solution, produce a trace or brute-force plan; when stuck take one hint, act on it, then reassess Record help used, the failing input, the corrected reasoning, and a next review date; start around 1/3/7/14/30 days and adapt Reserve a weekly mixed review; after foundation readiness add a short virtual contest and upsolve one task with known prerequisites Prove progress through a delayed blank-editor reconstruction and a changed problem; a same-day quiz is supporting evidence only
Contest Simulation & Permanent CP Toolkit Run a full timed virtual contest (a past Codeforces Div2 or CodeChef round), solve under contest rules, then upsolve every unsolved problem against editorials. Assemble a tested, reusable C++ template + snippet library covering every structure and algorithm in this course, plus a stress-testing harness and a personal pattern catalog.
After this phase, you'll be able to:
Game theory Constructive algorithms Interactive & randomized problems Ad-hoc, math & observation problems Contest strategy & a sustainable rating practice Capstone — a self-run contest simulation After Phase 25, explain a core invariant, reconstruct a solution after a delay, diagnose a bug, and solve one unlabelled variation. Repair a failed prerequisite before advancing; record help separately from independent work.