  We propose a variant of an algorithm introduced by Schewe and also studied by
Luttenberger for solving parity or mean-payoff games. We present it over energy
games and call our variant the ESL algorithm (for Energy-Schewe-Luttenberger).
We find that using potential reductions as introduced by Gurvich, Karzanov and
Khachiyan allows for a simple and elegant presentation of the algorithm, which
repeatedly applies a natural generalisation of Dijkstra's algorithm to the
two-player setting due to Khachiyan, Gurvich and Zhao.
