https://atcoder.jp/contests/abc035/tasks/abc035_d

  • Thoughts.
    • Sometimes it is more profitable to pay the travel cost and go to another city than to stay in the first city for T minutes and keep getting A1.
    • At this time, the destination city must have a larger Ai to gain
    • When moving from one city to another, staying in the middle of the city is not an optimal solution.
    • Therefore, “go to town i in the shortest distance, spend some time and come back” is the optimal solution, and find out which i is the correct answer.
    • First, use the Dijkstra method to find the shortest distance to each town
    • Choose the largest score
  • Official Explanation
    • WA: Problem condition misunderstanding, road is not two-way
    • The way home is not a single starting point
    • If we invert the → edge and do the Dijkstra method, we can also do the shortest path with a single endpoint.

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