Add run-length-encoding exercise (#38)

* Add run-length-encoding exercise

* Lint, config update

* Lint

abaplint_exercises.json

@@ -327,7 +327,7 @@
       "ignorePatterns": [],
       "local": "^LCL_.+$",
       "exception": "^LCX_.+$",
-      "test": "^LTCL_.+$"
+      "test": "^LT.+$"
     },
     "local_testclass_location": true,
     "local_variable_names": false,

abaplint_solutions.json

@@ -323,7 +323,7 @@
       "ignorePatterns": [],
       "local": "^LCL_.+$",
       "exception": "^LCX_.+$",
-      "test": "^LTCL_.+$"
+      "test": "^LT.+$"
     },
     "local_testclass_location": true,
     "local_variable_names": false,

config.json

@@ -108,6 +108,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
+      },
+      {
+        "slug": "run-length-encoding",
+        "name": "Run Length Encoding",
+        "uuid": "18479071-0e8a-4ba6-8a32-fb2ee40cc94c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
       }
     ]
   },

exercises/practice/run-length-encoding/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Description
+
+Implement run-length encoding and decoding.
+
+Run-length encoding (RLE) is a simple form of data compression, where runs
+(consecutive data elements) are replaced by just one data value and count.
+
+For example we can represent the original 53 characters with only 13.
+
+```text
+"WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB"  ->  "12WB12W3B24WB"
+```
+
+RLE allows the original data to be perfectly reconstructed from
+the compressed data, which makes it a lossless data compression.
+
+```text
+"AABCCCDEEEE"  ->  "2AB3CD4E"  ->  "AABCCCDEEEE"
+```
+
+For simplicity, you can assume that the unencoded string will only contain
+the letters A through Z (either lower or upper case) and whitespace. This way
+data to be encoded will never contain any numbers and numbers inside data to
+be decoded always represent the count for the following character.

exercises/practice/run-length-encoding/.meta/config.json

@@ -0,0 +1,13 @@
+{
+  "blurb": "Implement run-length encoding and decoding.",
+  "authors": ["pokrakam"],
+  "contributors": [
+  ],
+  "files": {
+    "solution": ["zcl_rle.clas.abap"],
+    "test": ["zcl_rle.clas.testclasses.abap"],
+    "example": [".meta/zcl_rle.clas.abap"]
+  },
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Run-length_encoding"
+}

exercises/practice/run-length-encoding/.meta/zcl_rle.clas.abap

@@ -0,0 +1,62 @@
+CLASS zcl_rle DEFINITION
+  PUBLIC
+  FINAL
+  CREATE PUBLIC .
+
+  PUBLIC SECTION.
+
+    METHODS encode IMPORTING input         TYPE string
+                   RETURNING VALUE(result) TYPE string.
+
+    METHODS decode IMPORTING input         TYPE string
+                   RETURNING VALUE(result) TYPE string.
+
+ENDCLASS.
+
+
+CLASS zcl_rle IMPLEMENTATION.
+
+  METHOD encode.
+
+    DATA: char       TYPE string,
+          duplicates TYPE string.
+
+    DATA(str) = input.
+
+    WHILE str IS NOT INITIAL.
+
+      FIND REGEX '([\w|\s])(\1*)(.*)' IN str SUBMATCHES char duplicates str  ##SUBRC_OK.
+
+      IF duplicates IS NOT INITIAL.
+        result = |{ result }{ strlen( duplicates ) + 1 }{ char }|.
+      ELSE.
+        result = |{ result }{ char }|.
+      ENDIF.
+
+    ENDWHILE.
+
+  ENDMETHOD.
+
+
+  METHOD decode.
+
+    DATA: char TYPE string,
+          reps TYPE string.
+
+    DATA(str) = input.
+
+    WHILE str IS NOT INITIAL.
+
+      FIND REGEX '(\d*)([\w|\s])(.*)' IN str SUBMATCHES reps char str  ##SUBRC_OK.
+
+      IF reps IS NOT INITIAL.
+        result = |{ result }{ repeat( val = char occ = reps ) }|.
+      ELSE.
+        result = |{ result }{ char }|.
+      ENDIF.
+
+    ENDWHILE.
+
+  ENDMETHOD.
+
+ENDCLASS.

exercises/practice/run-length-encoding/zcl_rle.clas.abap

@@ -0,0 +1,32 @@
+CLASS zcl_rle DEFINITION
+  PUBLIC
+  FINAL
+  CREATE PUBLIC .
+
+  PUBLIC SECTION.
+
+    METHODS encode IMPORTING input         TYPE string
+                   RETURNING VALUE(result) TYPE string.
+
+    METHODS decode IMPORTING input         TYPE string
+                   RETURNING VALUE(result) TYPE string.
+
+ENDCLASS.
+
+
+CLASS zcl_rle IMPLEMENTATION.
+
+  METHOD encode.
+
+    "Add solution here
+
+  ENDMETHOD.
+
+
+  METHOD decode.
+
+    "Add solution here
+
+  ENDMETHOD.
+
+ENDCLASS.

exercises/practice/run-length-encoding/zcl_rle.clas.testclasses.abap

@@ -0,0 +1,118 @@
+CLASS ltc_encode DEFINITION FINAL FOR TESTING
+  DURATION SHORT
+  RISK LEVEL HARMLESS.
+
+  PRIVATE SECTION.
+    DATA cut TYPE REF TO zcl_rle.
+
+    METHODS setup.
+
+    METHODS empty_string FOR TESTING RAISING cx_static_check.
+    METHODS no_repeat    FOR TESTING RAISING cx_static_check.
+    METHODS no_singles   FOR TESTING RAISING cx_static_check.
+    METHODS mixed_singles_and_repeats FOR TESTING RAISING cx_static_check.
+    METHODS mixed_and_spaces FOR TESTING RAISING cx_static_check.
+    METHODS lowercase        FOR TESTING RAISING cx_static_check.
+ENDCLASS.
+
+
+CLASS ltc_encode IMPLEMENTATION.
+
+  METHOD setup.
+    cut = NEW zcl_rle( ).
+  ENDMETHOD.
+
+  METHOD empty_string.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `` )
+                                        exp = `` ).
+  ENDMETHOD.
+
+  METHOD no_repeat.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `XYZ` )
+                                        exp = `XYZ` ).
+  ENDMETHOD.
+
+  METHOD no_singles.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `AABBBCCCC` )
+                                        exp = `2A3B4C` ).
+  ENDMETHOD.
+
+  METHOD mixed_singles_and_repeats.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB` )
+                                        exp = `12WB12W3B24WB` ).
+  ENDMETHOD.
+
+  METHOD mixed_and_spaces.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `  hsqq qww  ` )
+                                        exp = `2 hs2q q2w2 ` ).
+  ENDMETHOD.
+
+  METHOD lowercase.
+    cl_abap_unit_assert=>assert_equals( act = cut->encode( `aabbbcccc` )
+                                        exp = `2a3b4c` ).
+  ENDMETHOD.
+
+ENDCLASS.
+
+
+CLASS ltc_decode DEFINITION FINAL FOR TESTING
+  DURATION SHORT
+  RISK LEVEL HARMLESS.
+
+  PRIVATE SECTION.
+    DATA cut TYPE REF TO zcl_rle.
+
+    METHODS setup.
+
+    METHODS empty_string FOR TESTING RAISING cx_static_check.
+    METHODS no_repeat    FOR TESTING RAISING cx_static_check.
+    METHODS no_singles   FOR TESTING RAISING cx_static_check.
+    METHODS mixed_singles_and_repeats FOR TESTING RAISING cx_static_check.
+    METHODS mixed_and_spaces FOR TESTING RAISING cx_static_check.
+    METHODS lowercase        FOR TESTING RAISING cx_static_check.
+    METHODS encode_and_decode FOR TESTING RAISING cx_static_check.
+ENDCLASS.
+
+
+CLASS ltc_decode IMPLEMENTATION.
+
+  METHOD setup.
+    cut = NEW zcl_rle( ).
+  ENDMETHOD.
+
+  METHOD empty_string.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `` )
+                                        exp = `` ).
+  ENDMETHOD.
+
+  METHOD no_repeat.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `XYZ` )
+                                        exp = `XYZ` ).
+  ENDMETHOD.
+
+  METHOD no_singles.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `2A3B4C` )
+                                        exp = `AABBBCCCC` ).
+  ENDMETHOD.
+
+  METHOD mixed_singles_and_repeats.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `12WB12W3B24WB` )
+                                        exp = `WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB` ).
+  ENDMETHOD.
+
+  METHOD mixed_and_spaces.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `2 hs2q q2w2 ` )
+                                        exp = `  hsqq qww  ` ).
+  ENDMETHOD.
+
+  METHOD lowercase.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( `2a3b4c` )
+                                        exp = `aabbbcccc` ).
+  ENDMETHOD.
+
+  METHOD encode_and_decode.
+    cl_abap_unit_assert=>assert_equals( act = cut->decode( cut->encode( `zzz ZZ  zZ` ) )
+                                        exp = `zzz ZZ  zZ` ).
+  ENDMETHOD.
+
+ENDCLASS.