Hi community, I've come across this problem: https://leetcode.com/problems/find-the-safest-path-in-a-grid/description/

Issue: I've come across a solution to this problem where we can apply modified Dijkstra's algo and also transition to 0-1 BFS method Solution link: https://leetcode.com/problems/find-the-safest-path-in-a-grid/solutions/5158996/c-rust-o-n-2-no-dijkstra-pure-bfs-explained-beats-97-44

But I'm unable to understand how is the Queue being Monotonic here in the solution provided in above link.

It will be very helpful if someone may give me little insights about this.