Algorithm:An algorithm is a specific problem-solving strategy that guarantees finding the correct solution if one exists by following a precise set of rules or steps.
Heuristic:A heuristic is a general problem-solving strategy that provides shortcuts or rules of thumb to quickly find solutions without guaranteeing their correctness.
Trial-and-error: Trial-and-error is an informal problem-solving strategy where multiple attempts are made until the correct solution is found through experimentation.