Protip: if you spend more than 30 mins trying to solve a kata (especially if the satisfaction rating is below 90%), read the discourse. I solved this quickly because I looked at it!

Thanks I thought of it after asking the question lol. Just a minor adjustment from my previous thinking.

see below

armies can also move diagonally

For this test, goldMineRace([[1,6], [1,-4], [-4,1], [11,1], [4,5]],[1, 1, 1, 2, 1],[1, 1]),-1)
I wonder whether the answer should be 4, the last city? Why? Well, I think the first four cities' armies arrive at the same time, so they wipe each other out; then the last city, index 4, arrives and gets the gold mine.
city[0] has to go 5 at a speed of 1
city[1] has to go 5 at a speed of 1
city[2] has to go 5 at a speed of 1
city[3] has to go 10 at a speed of 2
city[4] has to go 7 at a speed of 1, so it arrives last, but alone. What am I missing here?

This is a terrible kata. The description is very unclear; I wasted several hours on it; waste of time!

Sorry, but I had the same question, and I do not see why your question is wrong. '3452' is shorter than 'wkppv'. Why is the former included and not the latter?