README updated

Author: ErianArcher

README.md

@@ -1,2 +1,29 @@
 # RandomStringAssembly
-A final project from the course, Algorithm, requires to rebuild a string with its substrings.
+A final project from the course, Algorithm, requires to rebuild a string with its substrings. This implementation of sequence assembly is based on **De Bruijn Graph**.
+## Prerequisite
+- MPICH 3.3.1
+- PTHREAD
+- C++ 11 supported
+## Build this project
+1. `mkdir build; cd build`
+2. `cmake ../`
+3. `make`
+
+## Run the program
+After executing the command above, a program named `RandomStringAssembly` is generated in the current directory. It should be run by the command of below:
+```
+mpiexec -np {the number of processes/hosts} ./RandomStringAssembly {the value of k of k-mer} {input folder} {the filename of the file of reads in the input folder}
+```
+. Multiple filenames can be splitted by white space following the argument of `{input folder}`.
+
+For example:
+
+- Command for running the program with 6 processes, k-mer with 79 characters, and input file named "reads" in the folder of "input".
+```
+mpiexec -np 6 ./RandomStringAssembly 79 "input" "reads"
+```
+
+- Command for running the program with 6 processes, k-mer with 79 characters, and input files named "reads1" and "reads2" in the folder of "input".
+```
+mpiexec -np 6 ./RandomStringAssembly 79 "input" "reads1" "reads2"
+```