Main(Input: S, MemForComm, BuffSize, OutputBuffSize)
1: i = MPI_Rank();
2: P = MPI_Size();
3: ifi >= 0 and i<kthen
4:  Read the ith partition of string S
5:  ProcTypeI(MemForComm,BuffSize,P)
6: end if
7: ifi >= k and i < P−1 then
8:  Read the ith partition of string S
9:  ProcTypeII(BuffSize)
10: end if
11: ifi == P−1 then
12:  ProcTypeIII(BuffSize,OutputBuffSize)
13: end if