TL;DR: The fastest algorithm looks at every element once, keeping track of the largest one seen so far. Details. Intuition tells us that any correct algorithm must look at every element in the array, that's why we can't do better. Let's find an actual proof.
Drugs are addictive  because they either mimic or stimulate the production of brain chemicals that cause feelings of pleasure. After a period of time, your brain adjusts to the higher levels of the chemicals, and it becomes necessary to use more drugs to get the same effect.
However, most addictive behavior is not related to either physical tolerance or exposure to cues. People commonly use drugs, gamble, or shop compulsively in reaction to stress, whether or not they have a physical addiction. Since these addictions are not based on drug or brain effects, they can account for why people frequently switch addictive actions from one drug to a completely different kind of drug, or even to a non-drug behavior. The focus of the addiction isn't what matters; it's the need to take action under certain kinds of stress.