Classic O(n) greedy gas-station algorithm:
walk once, tracking
total = sum of (gas[i] - cost[i]) -- if negative, no answer
curr = running tank since start -- on negative, advance
start past i+1 and reset
if total < 0 then -1 else start
For gas = [1;2;3;4;5], cost = [3;4;5;1;2], unique start = 3.
Tests `total` + `curr` parallel accumulators, reset-on-failure
pattern.
202 baseline programs total.
giles
fed07059a3