Formal Derivation of Two Algorithms Involving Sequences

Using formal method PAR, two algorithms involving sequences, a majority problem deterministic algorithmic solution and computing the mode, are derived. From formal functional specifications, problems are partitioned into sub-problems, problem solving recurrences are constructed through formal specification transformation, and then loop invariants are achieved naturally, the algorithms that can be further transformed into executable programs supported by PAR platform are obtained. Formal derivation using PAR makes the algorithm idea is exhibited naturally and clearly.