Roadmap Dan Ladder Sign in and link your AtCoder account to track dan progress with verified solves. Sign in 1st Dan Novice I/O, loops, conditionals, and first array problems 0/10 to pass · 20 problems 2nd Dan Pupil Simulation, counting, and straightforward greedy checks 0/10 to pass · 20 problems 3rd Dan Ashen Sorting, brute force, modular arithmetic, and first DP steps 0/10 to pass · 20 problems 4th Dan Sprout BFS/DFS, prefix sums, two pointers, and classic DP 0/10 to pass · 20 problems 5th Dan Torrent Graph traversal, DSU, binary search on the answer, and combinatorics 0/10 to pass · 20 problems 6th Dan Azure Shortest paths, subsequence DP, number theory, and clever counting 0/10 to pass · 20 problems 7th Dan Solar Binary lifting, bitmask DP, segment-tree thinking, and exchange arguments 0/10 to pass · 20 problems 8th Dan Ember Parallel binary search, digit tricks, and genuinely hard DP 0/10 to pass · 20 problems 9th Dan Crimson Game theory, rerooting tree DP, and inventive constructions 0/10 to pass · 20 problems Kaiden The hardest problems AtCoder has to offer. Good luck. 0/10 to pass · 20 problems