IOI 1992
All 3 IOI tasks from 1992, organized as individual solution pages.
Problem set
Each entry below goes straight to the public problem page, with the statement, editorial, code, and raw resources kept together.
Islands
Single Water Level: Flood Fill Mark each cell as land if elevation[r][c] > L. Count connected components of land cells using BFS. Multiple Water Levels: Offline DSU To answer Q queries efficiently: Sort all cells by e...
Points (Convex Hull)
Andrew's Monotone Chain Algorithm Sort all points lexicographically by (x, y). Lower hull: Scan left to right. Maintain a stack. For each new point, while the last two stack points and the new point make a non-left tu...
Teletext
Algorithm Load patterns: For each known character, store its h w pixel grid. Segment the image: Divide the input image into cells of size h w. Match each cell: Compare pixel-by-pixel against all patterns. For exact ma...