New publication work and the preserved historical corpus. The archive remains searchable and link-stable even when older material is no longer homepage identity.
I review the AI-agent pipeline I used at Japan's Ministry of Internal Affairs and Communications nationwide CTF, separating the official 26th-place, 5,701-point result from local tracker data and documenting gaps in orchestration, state, verification, and observability.
Archived technical note: GitHub Actions CI/CD for a Jekyll Site.
Archived technical note: BOJ 10803 — Making Squares: A Verified Recurrence Bound.
Archived technical note: Fast Fourier Transform (FFT).
Archived technical note: BOJ 1199 — Euler Circuit.
Archived technical note: Bolzano–Weierstrass Theorem.
Archived technical note: Monotone Convergence Theorem.
Archived technical note: Nested Interval Property.
Archived technical note: BOJ 7579 — App.
Archived technical note: Metric Spaces and Fundamental Definitions (2).
Archived technical note: Analysis - 解析学(1).
Archived technical note: Bézout's identity.
Archived technical note: 백준 1006번 - 습격자 초라기(증명).
Archived technical note: 백준 1035번 - 조각 움직이기.
Archived technical note: 백준 1395번 - 스위치.
Archived technical note: 백준 19565번 - 수열 만들기.
Archived technical note: 백준 3653번 - 영화 수집.
Archived technical note: Euclidean Algorithm.
Archived technical note: Flow network.
Archived technical note: Floyd-Warshall Algorithm.
Archived technical note: Max-flow min-cut theorem.
Archived technical note: BOJ. Cubing (5373).
Archived technical note: BOJ 7469 - K-th Number.
Archived technical note: BOJ 1520 - Downhill Paths.
Archived technical note: BOJ. Match The Numbers (2494).
Archived technical note: BOJ. Square (7626).
Archived technical note: BOJ. Line Group (2162).
Archived technical note: BOJ. Crossing Lines 3 (20149).
Archived technical note: BOJ 1069 - Going Home.
Archived technical note: BOJ. Two Circles (7869).
Archived technical note: BOJ. Crossing Lines (17386).
Archived technical note: BOJ. Crossing Lines 2 (17387).
Archived technical note: BOJ. The Area Of The Polygon (2166).
Archived technical note: BOJ. Passionate Gang-Ho 4 (11378).
Archived technical note: BOJ. Maximum Flow (6086).
Archived technical note: BOJ. Passionate Gang-Ho 2 (11376).
Archived technical note: BOJ. Passionate Gang-Ho (11375).
Archived technical note: BOJ. Palindrome Is Not A Palindrome (15927).
Archived technical note: BOJ. Allocating Cattle Shed (2188).
Archived technical note: BOJ. Round Trip From City To City (17412).
Archived technical note: BOJ. String And Query (13713).
Archived technical note: BOJ. Repeated Pattern (16229).
Archived technical note: AtCoder. ABC 238 C 1111gal password.
Archived technical note: AtCoder. ABC 238 D ABC Transform.
Archived technical note: BOJ. Report Problem No.15164 (16163).
Archived technical note: BOJ. Find Kth Shortest Path (1854).
Archived technical note: BOJ. Ship (1092).
Archived technical note: BOJ. Sensor (2212).
Archived technical note: BOJ. Castle Difense (17135).
Archived technical note: BOJ. Castle Difense (2473).
Archived technical note: BOJ. Puyo Puyo (11559).
Archived technical note: BOJ. King Of Fishing (17143).
Archived technical note: BOJ. Synthesize Solutions (14921).
Archived technical note: BOJ. Convey News (1135).
Archived technical note: BOJ. Make A Big Number (16496).
Archived technical note: BOJ. Cheese (2638).
Archived technical note: BOJ. Two-Dimenstion Array And Operation (17140).
Archived technical note: BOJ. CCW (11758).
Archived technical note: Tree Investment.
Archived technical note: BOJ. Four Numbers Of With Sum (7453).
Archived technical note: BOJ. Lecture Room Assignment (11000).
Archived technical note: BOJ. N th Biggest Number (2075).
Archived technical note: LeetCode. 1028. Recover a Tree From Preorder Traversal.
Archived technical note: BOJ. Race (2517).
Archived technical note: BOJ. Candy Box (2243).
Archived technical note: BOJ. Manipulate Ladder (15684).
Archived technical note: BOJ. Bind A Number (1744).
Archived technical note: BOJ. Scale (2437).
Archived technical note: BOJ. Perfect Binary Tree (9934).
Archived technical note: BOJ. Boggle (9202).
Archived technical note: BOJ. Save The Sheep (16437).
Archived technical note: BOJ. Distance Between Vertices (1761).
Archived technical note: BOJ 1240 — Distance Between Nodes.
Archived technical note: BOJ. Cheese (2636).
Archived technical note: BOJ. Is This Tree? (6416).
Archived technical note: BOJ. Dragon Curve (15685).
Archived technical note: BOJ. Factory (7578).
Archived technical note: BOJ. Company Culture 1 (14267).
Archived technical note: BOJ. Binary Tree (13325).
Archived technical note: BOJ. Tree (4256).
Archived technical note: BOJ. Height And Width Of Tree (2250).
Archived technical note: BOJ. Slope (14890).
Archived technical note: BOJ. LCA (11437).
Archived technical note: BOJ. Phone Number List (5052).
Archived technical note: Memo. To prove.
Archived technical note: BOJ 17144 — Fine Dust Simulation.
Archived technical note: BOJ 1339 - Word Math.
Archived technical note: BOJ 2169 — Robot Control.
Archived technical note: BOJ 15683 — CCTV Surveillance.
Archived technical note: BOJ. Population Movement (16234).
Archived technical note: BOJ. Marble Escape 2 (13460).
Archived technical note: BOJ. Tetromino (14500).
Archived technical note: BOJ 14503 — Robot Vacuum (14503).
Archived technical note: BOJ. Snake (3190).
Archived technical note: BOJ. Roll The Dice (14499).
Archived technical note: BOJ. Baby Shark (16236).
Archived technical note: BOJ. Chicken Delivery (15686).
Archived technical note: BOJ. Longest Palindrome Substring (13275).
Archived technical note: BOJ. Reason the fox came up to Island (17131).
Archived technical note: LeetCode. 43. Multiply Strings.
Archived technical note: BOJ. Minimum Value (10999).
Archived technical note: BOJ. Histogram (1725).
Archived technical note: BOJ. Sum of numbers 7 (2268).
Archived technical note: BOJ. Coffe Shop (1275).
Archived technical note: BOJ. Minimum Value (10868).
Archived technical note: BOJ. Water taxi (2836).
Archived technical note: BOJ. Northwesterly Wind (5419).
Archived technical note: BOJ. line Drawing (2170).
Archived technical note: BOJ. ATM (4013).
Archived technical note: Codeforces Round 771 (Div. 2) A. Reverse.
Archived technical note: Codeforces Round 771 (Div. 2) B. Odd Swap Sort.
Archived technical note: Codeforces Round 771 (Div. 2) C. Inversion Graph.
Archived technical note: Codeforces Round 771 (Div. 2) D. Big Brush.
Archived technical note: BOJ. 2-SAT - 4 (11281).
Archived technical note: AtCoder. Regular Contest 135 A Floor, Ceil Decomposition.
Archived technical note: AtCoder. Regular Contest 135 B Sum of Three Terms.
Archived technical note: AtCoder. Regular Contest 135 C XOR to All.
Archived technical note: Codeforces Global Round 19 B. MEX and Array.
Archived technical note: BOJ. Idol (3648).
Archived technical note: Codeforces Global Round 19 C. Andrew and Stones.
Archived technical note: Codeforces Global Round 19 A. Sorting Parts.
Archived technical note: LeetCode. 100. Same Tree.
Archived technical note: BOJ. 2-SAT - 3 (11280).
Archived technical note: BOJ. Tree and Query 2 (13511).
Archived technical note: BOJ. Soccer Tactics (3977).
Archived technical note: BOJ. Domino (4196).
Archived technical note: BOJ. Palindrome Devision (1509).
Archived technical note: BOJ. Find Minimum (11003).
Archived technical note: BOJ. Road Network (3176).
Archived technical note: BOJ. LCA 2 (11438).
Archived technical note: BOJ. Composite Function And Query (17435).
Archived technical note: BOJ. Lowest Common Ancestor (3584).
Archived technical note: BOJ. SeongYeon Park (1086).
Archived technical note: Codeforces Round 770 (Div. 2) A. Reverse and Concatenate.
Archived technical note: Codeforces Round 770 (Div. 2) B. Fortune Telling.
Archived technical note: BOJ. Traveling Salesman problem (2098).
Archived technical note: BOJ. RGB Distance 2 (17404).
Archived technical note: BOJ. Final Ranking (3665).
Archived technical note: BOJ. Workbook (1766).
Archived technical note: BOJ. Distributed Processing (1009).
Archived technical note: AtCoder. ABC 238 A Exponential or Quadratic.
Archived technical note: AtCoder. ABC 238 B Pizza.
Archived technical note: AtCoder. ABC 238 C digitnum.
Archived technical note: BOJ. Hue Circle (2482).
Archived technical note: BOJ. ACM Craft (1005).
Archived technical note: BOJ. Advertisement (1305).
Archived technical note: BOJ. Independent Set of Tree. (2213).
Archived technical note: BOJ. excellence town (1949).
Archived technical note: BOJ. Society Service(SNS) (2533).
Archived technical note: BOJ. Phone Keyboard (5670).
Archived technical note: BOJ. Clock pictures (10266).
Archived technical note: AtCoder. ABC 237 E Skiing.
Archived technical note: AtCoder. ABC 237 D LR insertion.
Archived technical note: AtCoder. ABC 237 C kasaka.
Archived technical note: AtCoder. ABC 237 B Matrix Transposition.
Archived technical note: AtCoder. ABC 237 A Not Overflow.
Archived technical note: BOJ. Find (1786).
Archived technical note: BOJ. String set (14425).
Archived technical note: BOJ. Ant tunnel (14725).
Archived technical note: BOJ. String square (4354).
Archived technical note: BOJ. Two Liquid (2470).
Archived technical note: BOJ. Knapsack problem (1450).
Archived technical note: BOJ. Sum of Two Numbers (3273).
Archived technical note: BOJ. Subsequence sum (1806).
Archived technical note: BOJ. Stick (1094).
Archived technical note: BOJ. Determine task (1311).
Archived technical note: BOJ. Line up (2252).
Archived technical note: BOJ. Matrix multiplication order (11049).
Archived technical note: BOJ. Consecutive prime sum (1644).
Archived technical note: BOJ. Set (11723).
Archived technical note: BOJ. Strongly Connected Component (2150).
Archived technical note: BOJ. Tree And Query (15681).
Archived technical note: BOJ. Make Bridge(2) (17472).
Archived technical note: BOJ. Planet Tunnel (2887).
Archived technical note: BOJ. MST (Minimum Spanning Tree) (1197).
Archived technical note: BOJ. Digital Video Disk (9345).
Archived technical note: BOJ. Josephus problem(2) (1168).
Archived technical note: BOJ. Data Structure (12899).
Archived technical note: BOJ. Police Car (2618).
Archived technical note: BOJ. Array and Query (16975).
Archived technical note: AtCoder. ABC 235 D - Multiply and Rotate.
Archived technical note: AtCoder. ABC 235 A - Rotate.
Archived technical note: AtCoder. ABC 235 B Climbing Takahashi.
Archived technical note: AtCoder. ABC 235 C The Kth Time Query.
Archived technical note: BOJ. Floyd(2) (11780).
Archived technical note: BOJ. Get Miminum Cost(2) (11779).
Archived technical note: BOJ. DSLR (9019).
Archived technical note: BOJ. Hide And Sick(4) (13913).
Archived technical note: BOJ. LCS 2 (9252).
Archived technical note: BOJ. Longest Increasing Subsequence(5) (14003).
Archived technical note: BOJ. Longest Increasing Subsequence(4) (14002).
Archived technical note: BOJ. Make into 1(2) (12852).
Archived technical note: BOJ. Iterate Tree (2263).
Archived technical note: BOJ. Bubble Sort (1517).
Archived technical note: BOJ. Tree Iteration (1991).
Archived technical note: BOJ. Diameter of Tree (1967).
Archived technical note: BOJ. Diameter of Tree (1167).
Archived technical note: BOJ. Find Parent In Tree (11725).
Archived technical note: BOJ. Maximum and Minimum Values (2357).
Archived technical note: BOJ. Binary Search Tree (5639).
Archived technical note: BOJ. Cycle game (20040).
Archived technical note: LeetCode. 131. Palindrome Partitioning.
Archived technical note: BOJ. Friend Network (4195).
Archived technical note: BOJ. Let's go on a trip (1976).
Archived technical note: BOJ. Merge Files (11066).
Archived technical note: BOJ. Exercise (1956).
Archived technical note: BOJ. KCM Travel (10217).
Archived technical note: BOJ. Floyd (11404).
Archived technical note: LeetCode. 997. Find the Town Judge.
Archived technical note: BOJ. Time Machine (11657).
Archived technical note: BOJ. Unidentified destination (9370).
Archived technical note: LeetCode. 312. Burst Balloons.
Archived technical note: BOJ. Shortest path with specification (1504).
Archived technical note: BOJ. Prefix Product (11505).
Archived technical note: BOJ. Shortest Path (1753).
Archived technical note: Programmers. Network.
Archived technical note: BOJ. Bipartite Graph (1707).
Archived technical note: BOJ. Move the Knight (7562).
Archived technical note: LeetCode. 40. Combination Sum II.
Archived technical note: AtCoder. 020 Log Inequality(3).
Archived technical note: AtCoder. 018 Statue of Chokudai(3).
Archived technical note: AtCoder. 014 We Used to Sing a Song Together(3).
Archived technical note: AtCoder. 015 Don't be too close(6).
Archived technical note: AtCoder. 016 Minimum Coins(3).
Archived technical note: AtCoder. 013 Passing(5).
Archived technical note: AtCoder. 009 Three Point Angle(6).
Archived technical note: AtCoder. 010 Score Sum Queries(2).
Archived technical note: AtCoder. 011 Gravy Jobs(6).
Archived technical note: AtCoder. 012 Red Painting(4).
Archived technical note: AtCoder. 008 AtCounter(4).
Archived technical note: AtCoder. 007 CP Classes(3).
Archived technical note: AtCoder. 006 Smallest Subsequence(5).
Archived technical note: AtCoder. 005 Restricted Digits(7).
Archived technical note: AtCoder. 004 Cross Sum(2).
Archived technical note: AtCoder. 001 Yokan Party(4).
Archived technical note: AtCoder. 002 Encyclopedia of Parentheses(3).
Archived technical note: AtCoder. 003 Longest Circular Road(4).
Archived technical note: BOJ. Expression of Set (1717).
Archived technical note: LeetCode. 39. Combination Sum.
Archived technical note: BOJ. Move and break wall (2206).
Archived technical note: BOJ. Prefix sum (2042).
Archived technical note: BOJ. Hide and Seek (1697).
Archived technical note: Programmers. Find number of animals with same name.
Archived technical note: Programmers — Largest Number.
Archived technical note: LeetCode. 38. Count and Say.
Archived technical note: BOJ. Tomato (7569).
Archived technical note: LeetCode. 37. Sudoku Solver.
Archived technical note: LeetCode. 36. Valid Sudoku.
Archived technical note: BOJ. Tell Median Value (1655).
Archived technical note: LeetCode. 33. Search in Rotated Sorted Array.
Archived technical note: LeetCode. 34. Find First and Last Position of Element in Sorted Array.
Archived technical note: LeetCode. 32. Longest Valid Parentheses.
Archived technical note: BOJ. Maximum heap (11279).
Archived technical note: Codility. ArrayInversionCount.
Archived technical note: LeetCode. 35. Search Insert Position.
Archived technical note: LeetCode. 31. Next Permutation.
Archived technical note: LeetCode. 30. Substring with Concatenation of All Words.
Archived technical note: LeetCode. 29. Divide Two Integers.
Archived technical note: Programmers. Stock Price.
Archived technical note: Programmers. Disk Controller.
Archived technical note: BOJ. Closest two Point (2261).
Archived technical note: LeetCode. 28. Implement strStr().
Archived technical note: LeetCode. 27. Remove Element.
Archived technical note: LeetCode. 26. Remove Duplicates from Sorted Array.
Archived technical note: BOJ. Bigest square in histogram (6549).
Archived technical note: LeetCode. 25. Reverse Nodes in k-Group.
Archived technical note: LeetCode. 24. Swap Nodes in Pairs.
Archived technical note: LeetCode. 23. Merge k Sorted Lists.
Archived technical note: LeetCode. 21. Merge Two Sorted Lists.
Archived technical note: LeetCode. 10. Regular Expression Matching.
Archived technical note: LeetCode. 17. Letter Combinations of a Phone Number.
Archived technical note: LeetCode. 20. Valid Parentheses.
Archived technical note: AtCoder Typical 90 021 — Come Back in One Piece.
Archived technical note: Graph theory. Strongly Connected Component(SCC).
Archived technical note: LeetCode. 19. Remove Nth Node From End of List.
Archived technical note: De Moivre's formula.
Archived technical note: LeetCode. 1. Two Sum.
Archived technical note: LeetCode. 461. Hamming Distance.
Archived technical note: LeetCode. 540. Single Element in a Sorted Array.
Archived technical note: LeetCode 94. Binary Tree Inorder Traversal.
Archived technical note: BOJ 11659 — Range Sum Query 4.
Archived technical note: LeetCode. 53. Maximum Subarray.
Archived technical note: LeetCode. 13. Roman to Integer.
Archived technical note: LeetCode. 83. Remove Duplicates from Sorted List.
Archived technical note: AtCoder. 019 Pick Two(6).
Archived technical note: Contact.
Archived technical note: LeetCode. 14. Longest Common Prefix.
Archived technical note: LeetCode. 11. Container With Most Water.
Archived technical note: LeetCode. 12.Integer to Roman.
Archived technical note: LeetCode. 15. 3Sum.
Archived technical note: LeetCode. 16. 3Sum Closest.
Archived technical note: LeetCode. 3. Longest Substring Without Repeating Characters.
Archived technical note: LeetCode. 4 Median of Two Sorted Arrays.
Archived technical note: LeetCode. 5. Longest Palindromic Substring.
Archived technical note: LeetCode. 6. ZigZag Conversion.
Archived technical note: LeetCode. 7. Reverse Integer.
Archived technical note: LeetCode. 9. Palindrome Number.
Archived technical note: Sort. Radix Sort.
Archived technical note: BOJ. Tree (4803).