Problem · Graph

Minimum Direction Violations

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Problem statement

You are given a directed graph with n vertices numbered from 0 to n - 1. Each pair [u, v] in edges is an original directed edge from u to v.

You may traverse every listed edge in either direction:

The problem statement continues
Pro

Examples

Example 1

n = 5edges = [[0,1],[2,1],[2,3],[4,3]]start = 0end = 4return = 2

Follow 0 -> 1, reverse 2 -> 1 to move 1 -> 2, follow 2 -> 3, and reverse 4 -> 3 to move 3 -> 4. Exactly two traversals oppose their original directions, and no path uses fewer violations.

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FastPrep Pro
Reported in 1 Google interview this week

Unlock this recently reported problem

FastPrep Pro gives you full access to interview problems reported within the last week.

  • Full problem statement and constraints
  • 2 more worked examples, explained
  • Guided hints and editorial
  • Run your code on real test cases
$9/month

Pro subscription, billed yearly — or $19 month-to-month. Cancel anytime.

Free plan — 2 of 2 free unlocks used this week