| #501 | SubwayNordic Olympiad in Informatics 2017 | |
| #502 | Yule LadsNordic Olympiad in Informatics 2017 | |
| #503 | IP over Avian CarrierNordic Olympiad in Informatics 2017Communication | |
| #504 | ChessboardIZhO 2018 Day 1 | |
| #505 | Evacuation planIZhO 2018 Day 1 | |
| #506 | GiftIZhO 2018 Day 1 | |
| #507 | SegmentsIZhO 2018 Day 2 | |
| #508 | Nice sequenceIZhO 2018 Day 2 | |
| #509 | Birthday giftIZhO 2018 Day 2 | |
| #510 | Car VetEast Central NA Regional 2018 | |
| #511 | DifferenceEast Central NA Regional 2018 | |
| #512 | Pear-wise VotingEast Central NA Regional 2018 | |
| #513 | Pizza CuttingEast Central NA Regional 2018 | |
| #514 | The Punctilious CruciverbalistEast Central NA Regional 2018 | |
| #515 | A Random ProblemEast Central NA Regional 2018 | |
| #516 | Roman HolidaysEast Central NA Regional 2018 | |
| #517 | Sequential YahtzeeEast Central NA Regional 2018 | |
| #518 | Tours de Sales ForceEast Central NA Regional 2018 | |
| #519 | Watch Where You StepEast Central NA Regional 2018 | |
| #520 | 潜入行动JSOI 2018 Round 2 Day 1 | |
| #521 | 防御网络JSOI 2018 Round 2 Day 1 | |
| #522 | 绝地反击JSOI 2018 Round 2 Day 1 | |
| #523 | 部落战争JSOI 2018 Round 2 Day 2 | |
| #524 | 扫地机器人JSOI 2018 Round 2 Day 2 | |
| #525 | 军训列队JSOI 2018 Round 2 Day 2 | |
| #526 | MagiceJOI 2017 Day 1 | |
| #527 | ParticleseJOI 2017 Day 1 | |
| #528 | SixeJOI 2017 Day 1 | |
| #529 | CameleJOI 2017 Day 2 | |
| #530 | ExperienceeJOI 2017 Day 2 | |
| #531 | GameeJOI 2017 Day 2 | |
| #532 | 区间本质不同子串 | |
| #547 | BM 算法模板题BM 算法 | |
| #548 | 棋盘WC 2017 | |
| #549 | 挑战WC 2017 | |
| #550 | 排序WC 2017 | |
| #552 | 字符串匹配问题字符串DFT | |
| #553 | 王国JSOI 2017 Round 1 Day 1 | |
| #554 | 预言JSOI 2017 Round 1 Day 1 | |
| #555 | 代码JSOI 2017 Round 1 Day 1 | |
| #556 | 骑士JSOI 2017 Round 1 Day 2 | |
| #557 | 街道JSOI 2017 Round 1 Day 2 | |
| #558 | 奥术JSOI 2017 Round 1 Day 2 | |
| #559 | 原力JSOI 2017 Round 2 Day 1 | |
| #560 | 隧道JSOI 2017 Round 2 Day 1 | |
| #561 | 税收JSOI 2017 Round 2 Day 1 | |
| #562 | 码农JSOI 2017 Round 2 Day 2 | |
| #563 | 博弈JSOI 2017 Round 2 Day 2 | |
| #564 | 魔法JSOI 2017 Round 2 Day 2 | |