#3650

Minimum Cost Path with Edge Reversals

medium · 61.8% accepted · 456 likes · top 62%

graph theory · heap (priority queue) · shortest path

⊣ practice⊣ open on leetcode ↗

Description

You are given a directed, weighted graph with n nodes labeled from 0 to n - 1, and an array edges where edges[i] = [ui, vi, wi] represents a directed edge from node ui to node vi with cost wi.

Each node ui has a switch that can be used at most once: when you arrive at ui and have not yet used its switch, you may activate it on one of its incoming edges vi → ui reverse that edge to ui → vi and immediately traverse it.

The reversal is only valid for that single move, and using a reversed edge costs 2 * wi.

Return the minimum total cost to travel from node 0 to node n - 1. If it is not possible, return -1.

Solution