Final answer:
Didi's post-merger actions of forming alliances with Uber competitors and undermining Uber in global markets characterize it as a Reactor, as per the typology by Miles and Snow.
Step-by-step explanation:
Based on the competitive strategies employed by Didi after its acquisition of Uber China, the company could be characterized by the Reactor strategic type, as defined by Professors Miles and Snow in their 1978 book.
A Reactor is a company that does not have a consistent strategic approach but instead reacts to changes in the external environment often in an ad hoc and disjointed manner. In this case, Didi's actions to form strategic alliances with Uber's competitors in various global markets, even after the merger with Uber China, suggest an approach that responds to competitive pressures without a clear and consistent overarching strategy.
This behavior is indicative of a Reactor type, which does not proactively pursue a definitive strategy but rather reacts to the strategic moves of competitors and changes in the market.