Graphs, Trees and Schedules

Not every problem on the Optiver assessment is a simulation. A few are graph problems, and they lean on input handling as much as on the search itself, because two of them hand you one line of text in a strict format along with a ranked list of error codes. Running Dijkstra on 26 letters is quick. Getting every error code right takes longer.

Error codes come with a priority. When an input breaks two rules at once, only one code is correct, and the statement tells you which one. An input that breaks a format rule and a structure rule, for example, gets the format error. So run the checks in the stated order and stop at the first one that fires.

The other problems need the right state before the search becomes standard. In one, each node carries a window that its parents narrow. In another, a clock decides who reports first. The trickiest needs more than a position as its state, since part of the board can change during the search. Below, each problem gets its own walkthrough, starting with the tree check.

OptiverPremium lesson · Coding round

The 5 Optiver problems are below.

1. 1A Premium questionCoding · Medium · Frequently asked
2. 2A Premium questionCoding · Hard
3. 3A Premium questionCoding · Hard

+ 2 more in this lesson

Each with hints, the follow-up and a tested solution.

Get the Optiver questions

$49 a year · all 100 companies · cancel anytime

From 20,000+ candidate reports, forum threads behind logins and write-ups in Chinese.

Read a free Optiver lesson firstAlready a member? Sign in