Add robot-simulator exercise (#75)

Author: keiravillekode

config.json

@@ -468,6 +468,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "robot-simulator",
+        "name": "Robot Simulator",
+        "uuid": "189e3b7f-6b74-4333-b0f9-b3b4a218f899",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "affine-cipher",
         "name": "Affine Cipher",

exercises/practice/robot-simulator/.docs/instructions.md

@@ -0,0 +1,25 @@
+# Instructions
+
+Write a robot simulator.
+
+A robot factory's test facility needs a program to verify robot movements.
+
+The robots have three possible movements:
+
+- turn right
+- turn left
+- advance
+
+Robots are placed on a hypothetical infinite grid, facing a particular direction (north, east, south, or west) at a set of {x,y} coordinates,
+e.g., {3,8}, with coordinates increasing to the north and east.
+
+The robot then receives a number of instructions, at which point the testing facility verifies the robot's new position, and in which direction it is pointing.
+
+- The letter-string "RAALAL" means:
+  - Turn right
+  - Advance twice
+  - Turn left
+  - Advance once
+  - Turn left yet again
+- Say a robot starts at {7, 3} facing north.
+  Then running this stream of instructions should leave it at {9, 4} facing west.

exercises/practice/robot-simulator/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "RobotSimulator.pas"
+    ],
+    "test": [
+      "TestCases.pas"
+    ],
+    "example": [
+      ".meta/example.pas"
+    ]
+  },
+  "blurb": "Write a robot simulator.",
+  "source": "Inspired by an interview question at a famous company."
+}

exercises/practice/robot-simulator/.meta/example.pas

@@ -0,0 +1,84 @@
+unit RobotSimulator;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+type
+  TPosition = record
+    x: Int64;
+    y: Int64;
+  end;
+
+  TDirection = (north, east, south, west);
+
+  TRobot = class
+  private
+    fpos: TPosition;
+    fdir: TDirection;
+  public
+    constructor Create(const pos: TPosition; const dir: TDirection);
+    procedure Move(const instructions : String);
+    function ToString: String; override;
+  end;
+
+implementation
+
+uses SysUtils;
+
+constructor TRobot.Create(const pos: TPosition; const dir: TDirection);
+begin
+  fpos := pos;
+  fdir := dir;
+end;
+
+procedure TRobot.Move(const instructions : String);
+var
+  c : Char;
+begin
+  for c in instructions do
+    case c of
+      'R':
+        case fdir of
+          north: fdir := east;
+          east: fdir := south;
+          south: fdir := west;
+          west: fdir := north;
+        end;
+      'L':
+        case fdir of
+          north: fdir := west;
+          east: fdir := north;
+          south: fdir := east;
+          west: fdir := south;
+        end;
+      'A':
+        case fdir of
+          north: fpos.y := fpos.y + 1;
+          east: fpos.x := fpos.x + 1;
+          south: fpos.y := fpos.y - 1;
+          west: fpos.x := fpos.x - 1;
+        end;
+    else
+      raise Exception.Create('invalid instruction');
+    end;
+end;
+
+function TRobot.ToString: String;
+var
+  direction : String;
+begin
+  case fdir of
+    north:
+      direction := 'N';
+    east:
+      direction := 'E';
+    south:
+      direction := 'S';
+    west:
+      direction := 'W';
+  end;
+  result := format('%d,%d %s', [fpos.x, fpos.y, direction]);
+end;
+
+end.

exercises/practice/robot-simulator/.meta/tests.toml

@@ -0,0 +1,64 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[c557c16d-26c1-4e06-827c-f6602cd0785c]
+description = "Create robot -> at origin facing north"
+
+[bf0dffce-f11c-4cdb-8a5e-2c89d8a5a67d]
+description = "Create robot -> at negative position facing south"
+
+[8cbd0086-6392-4680-b9b9-73cf491e67e5]
+description = "Rotating clockwise -> changes north to east"
+
+[8abc87fc-eab2-4276-93b7-9c009e866ba1]
+description = "Rotating clockwise -> changes east to south"
+
+[3cfe1b85-bbf2-4bae-b54d-d73e7e93617a]
+description = "Rotating clockwise -> changes south to west"
+
+[5ea9fb99-3f2c-47bd-86f7-46b7d8c3c716]
+description = "Rotating clockwise -> changes west to north"
+
+[fa0c40f5-6ba3-443d-a4b3-58cbd6cb8d63]
+description = "Rotating counter-clockwise -> changes north to west"
+
+[da33d734-831f-445c-9907-d66d7d2a92e2]
+description = "Rotating counter-clockwise -> changes west to south"
+
+[bd1ca4b9-4548-45f4-b32e-900fc7c19389]
+description = "Rotating counter-clockwise -> changes south to east"
+
+[2de27b67-a25c-4b59-9883-bc03b1b55bba]
+description = "Rotating counter-clockwise -> changes east to north"
+
+[f0dc2388-cddc-4f83-9bed-bcf46b8fc7b8]
+description = "Moving forward one -> facing north increments Y"
+
+[2786cf80-5bbf-44b0-9503-a89a9c5789da]
+description = "Moving forward one -> facing south decrements Y"
+
+[84bf3c8c-241f-434d-883d-69817dbd6a48]
+description = "Moving forward one -> facing east increments X"
+
+[bb69c4a7-3bbf-4f64-b415-666fa72d7b04]
+description = "Moving forward one -> facing west decrements X"
+
+[e34ac672-4ed4-4be3-a0b8-d9af259cbaa1]
+description = "Follow series of instructions -> moving east and north from README"
+
+[f30e4955-4b47-4aa3-8b39-ae98cfbd515b]
+description = "Follow series of instructions -> moving west and north"
+
+[3e466bf6-20ab-4d79-8b51-264165182fca]
+description = "Follow series of instructions -> moving west and south"
+
+[41f0bb96-c617-4e6b-acff-a4b279d44514]
+description = "Follow series of instructions -> moving east and north"

exercises/practice/robot-simulator/Makefile

@@ -0,0 +1,15 @@
+SHELL       = /bin/bash
+MAKEFLAGS  += --no-print-directory
+DESTDIR     = build
+EXECUTABLE  = $(DESTDIR)/test
+COMMAND     = fpc -l- -v0 -g -gl -Sa -Cr -Sehnw -Fu./lib test.pas -FE"./$(DESTDIR)"
+
+.ONESHELL:
+
+test:
+	@mkdir -p "./$(DESTDIR)"
+	@cp -r ./lib "./$(DESTDIR)"
+	@$(COMMAND) && ./$(EXECUTABLE) $(test)
+
+clean:
+	@rm -fr "./$(DESTDIR)"

exercises/practice/robot-simulator/RobotSimulator.pas

@@ -0,0 +1,46 @@
+unit RobotSimulator;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+type
+  TPosition = record
+    x: Int64;
+    y: Int64;
+  end;
+
+  TDirection = (north, east, south, west);
+
+  TRobot = class
+  private
+    { Please implement your solution. }
+  public
+    constructor Create(const pos: TPosition; const dir: TDirection);
+    procedure Move(const instructions : String);
+    function ToString: String; override;
+  end;
+
+implementation
+
+uses SysUtils;
+
+constructor TRobot.Create(const pos: TPosition; const dir: TDirection);
+begin
+  if (pos.x = pos.x) and (pos.y = pos.y) and (dir = dir) then
+    raise ENotImplemented.Create('Please implement your solution.');
+end;
+
+procedure TRobot.Move(const instructions : String);
+begin
+  if instructions = instructions then
+    raise ENotImplemented.Create('Please implement your solution.');
+end;
+
+function TRobot.ToString: String;
+begin
+  raise ENotImplemented.Create('Please implement your solution.');
+  result := '';
+end;
+
+end.