Floyd algorithm for calculating multi-source Shortest Path-----

title Link: Https://vjudge.net/contest/146629#problem/L

Title Description: There are n planets, starting at the first planet, seeking to travel all the planet's arrival time and minimum value

Problem Solving Process:

The time required for the first planet to reach the J Planet is T[i][j]

Processing the Floyd algorithm will give the minimum time required for Planet I to reach the J Planet:

     for 1; K <= N; k++)        for1; I <= N; i++)            for1; J <= N; J + +)                = min (T[i][k] + t[k][j], t[i][j]);

Then use DFS to search each planet.

Pruning:

① Current time + time required from the planet to all non-arrival planets < All time limits for the planet not arriving

② (important) current arrival time and + (n -reach planet number) * Current arrival time < known minimum result

Why does the Floyd algorithm put K on the outermost layer? ------Know https://www.zhihu.com/question/30955032

Floyd algorithm for calculating multi-source Shortest path-----