Add robot-simulator

config.json

@@ -528,6 +528,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
+      },
+      {
+        "slug": "robot-simulator",
+        "name": "Robot Simulator",
+        "uuid": "b89d7805-b71f-45f9-929d-4f1ea8f695e9",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
       }
     ]
   },

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": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "source/robot_simulator.d"
+    ],
+    "test": [
+      "source/robot_simulator.d"
+    ],
+    "example": [
+      "example/robot_simulator.d"
+    ]
+  },
+  "blurb": "Write a robot simulator.",
+  "source": "Inspired by an interview question at a famous company."
+}

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/dub.sdl

@@ -0,0 +1,2 @@
+name "robot-simulator"
+buildRequirements "disallowDeprecations"

exercises/practice/robot-simulator/example/robot_simulator.d

@@ -0,0 +1,64 @@
+module robot_simulator;
+
+string[string][string] directions;
+
+shared static this()
+{
+    directions["north"] = ["left": "west", "right": "east"];
+    directions["east"] = ["left": "north", "right": "south"];
+    directions["south"] = ["left": "east", "right": "west"];
+    directions["west"] = ["left": "south", "right": "north"];
+}
+
+class RobotSimulator
+{
+public:
+    this(int x, int y, string direction)
+    {
+        this.x = x;
+        this.y = y;
+        this.direction = direction;
+    }
+
+    void move(string commands)
+    {
+        foreach (command; commands)
+        {
+            if (command == 'A')
+            {
+                advance();
+            } else
+            {
+                rotate(command);
+            }
+        }
+    }
+
+private:
+    void rotate(char command)
+    {
+        string key = command == 'L' ? "left" : "right";
+        this.direction = directions[this.direction][key];
+    }
+
+    void advance()
+    {
+        if (this.direction == "north")
+        {
+            this.y += 1;
+        } else if (this.direction == "east")
+        {
+            this.x += 1;
+        } else if (this.direction == "south")
+        {
+            this.y -= 1;
+        } else if (this.direction == "west")
+        {
+            this.x -= 1;
+        }
+    }
+
+    int x;
+    int y;
+    string direction;
+}

exercises/practice/robot-simulator/source/robot_simulator.d

@@ -0,0 +1,183 @@
+module robot_simulator;
+
+class RobotSimulator
+{
+    this(int x, int y, string direction)
+    {
+        // implement this function
+    }
+
+    void move(string commands)
+    {
+        // implement this function
+    }
+}
+
+unittest
+{
+    immutable int allTestsEnabled = 0;
+
+    // Create robot at origin facing north
+    {
+        RobotSimulator robot = new RobotSimulator(0, 0, "north");
+        assert(robot.x == 0);
+        assert(robot.y == 0);
+        assert(robot.direction == "north");
+    }
+
+    static if (allTestsEnabled)
+    {
+        // Create robot at negative position facing south
+        {
+            RobotSimulator robot = new RobotSimulator(-1, -1, "south");
+            assert(robot.x == -1);
+            assert(robot.y == -1);
+            assert(robot.direction == "south");
+        }
+
+        // Rotating clockwise changes north to east
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "north");
+            robot.move("R");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "east");
+        }
+
+        // Rotating clockwise changes east to south
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "east");
+            robot.move("R");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "south");
+        }
+
+        // Rotating clockwise changes south to west
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "south");
+            robot.move("R");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "west");
+        }
+
+        // Rotating clockwise changes west to north
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "west");
+            robot.move("R");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "north");
+        }
+
+        // Rotating counter-clockwise changes north to west
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "north");
+            robot.move("L");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "west");
+        }
+
+        // Rotating counter-clockwise changes west to south
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "west");
+            robot.move("L");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "south");
+        }
+
+        // Rotating counter-clockwise changes south to east
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "south");
+            robot.move("L");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "east");
+        }
+
+        // Rotating counter-clockwise changes east to north
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "east");
+            robot.move("L");
+            assert(robot.x == 0);
+            assert(robot.y == 0);
+            assert(robot.direction == "north");
+        }
+
+        // Moving forward one facing north increments Y
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "north");
+            robot.move("A");
+            assert(robot.x == 0);
+            assert(robot.y == 1);
+            assert(robot.direction == "north");
+        }
+
+        // Moving forward one facing south decrements Y
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "south");
+            robot.move("A");
+            assert(robot.x == 0);
+            assert(robot.y == -1);
+            assert(robot.direction == "south");
+        }
+
+        // Moving forward one facing east increments X
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "east");
+            robot.move("A");
+            assert(robot.x == 1);
+            assert(robot.y == 0);
+            assert(robot.direction == "east");
+        }
+
+        // Moving forward one facing west decrements X
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "west");
+            robot.move("A");
+            assert(robot.x == -1);
+            assert(robot.y == 0);
+            assert(robot.direction == "west");
+        }
+
+        // Follow series of instructions moving east and north from README
+        {
+            RobotSimulator robot = new RobotSimulator(7, 3, "north");
+            robot.move("RAALAL");
+            assert(robot.x == 9);
+            assert(robot.y == 4);
+            assert(robot.direction == "west");
+        }
+
+        // Follow series of instructions moving west and north
+        {
+            RobotSimulator robot = new RobotSimulator(0, 0, "north");
+            robot.move("LAAARALA");
+            assert(robot.x == -4);
+            assert(robot.y == 1);
+            assert(robot.direction == "west");
+        }
+
+        // Follow series of instructions moving west and south
+        {
+            RobotSimulator robot = new RobotSimulator(2, -7, "east");
+            robot.move("RRAAAAALA");
+            assert(robot.x == -3);
+            assert(robot.y == -8);
+            assert(robot.direction == "south");
+        }
+
+        // Follow series of instructions moving east and north
+        {
+            RobotSimulator robot = new RobotSimulator(8, 4, "south");
+            robot.move("LAAARRRALLLL");
+            assert(robot.x == 11);
+            assert(robot.y == 5);
+            assert(robot.direction == "north");
+        }
+    }
+
+}