/ DSA with C++ / Phase 23 Phase 23 Days 129-134
Advanced Graphs The graph theory that separates strong CP: SCC, bridges, LCA, flows, matching
Phase Goal Build the high-end graph algorithms on top of the DFS tree and low-link machinery.
Day 129: DFS tree, bridges & articulation points
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 130: Strongly connected components
Tarjan's SCC & 2-SAT (intro)
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 131: LCA & binary lifting
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 132: Heavy-light decomposition (intro) & tree queries
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 133: Network flow
Dinic's algorithm (intro)
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 134: Bipartite matching & recap
Assignment & applications
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
After this phase, you'll be able to:
DFS tree, bridges & articulation points Strongly connected components LCA & binary lifting Heavy-light decomposition (intro) & tree queries Network flow Bipartite matching & recap After Phase 23, 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.