Assignment2 algorithm solution.

README.md

@@ -1,13 +1,12 @@
-# Advent of Code 2022 - Assignment5 javascript
-This repository contains answers to the assignments of Advent of Coding 2022
+# Advent of Code 2022 - assignment2 javascript
+## Description
+Assignment2 involves a game of rock paper scissors. The solution uses an enum for rock, paper, scissor values it defines two functions for selecting a winning and losing hand. The winning and losing hand take advantage of the fact that each next value in the rock, paper, scissor trio beats the previous (looping back to rock). For losing it is the other way around. The winning_hand function is also used to determine the score for player. In the GUI there is a checkbox for selecting solution options (part1,part2).
 
 ## References
-- https://www.w3schools.com/jsref/jsref_includes.asp
-- https://stackoverflow.com/questions/10261986/how-to-detect-string-which-contains-only-spaces
-- https://www.w3schools.com/jsref/jsref_indexof.asp
-- https://stackoverflow.com/questions/8073673/how-can-i-add-new-array-elements-at-the-beginning-of-an-array-in-javascript
-- https://stackoverflow.com/questions/966225/how-can-i-create-a-two-dimensional-array-in-javascript
-- https://www.w3schools.com/jsref/jsref_ceil.asp
-- https://stackoverflow.com/questions/30561056/console-log-a-multi-dimensional-array
-- https://teamtreehouse.com/community/removing-more-than-1-element-using-pop-and-shift-method
-- https://stackoverflow.com/questions/14723848/push-multiple-elements-to-array
+- https://www.psychologytoday.com/us/blog/the-blame-game/201504/the-surprising-psychology-rock-paper-scissors#:~:text=There%20are%20four%20possible%20outcomes,Douglas%20Walker%20and%20Graham%20Walker.
+- https://www.sohamkamani.com/javascript/enums/
+- https://codingbeautydev.com/blog/javascript-remove-all-whitespace-from-string/#:~:text=To%20remove%20all%20whitespace%20from%20a%20string%20in%20JavaScript%2C%20call,all%20whitespace%20removed%20from%20str%20.
+- https://www.geeksforgeeks.org/how-to-check-a-key-exists-in-javascript-object/#:~:text=There%20are%20mainly%20two%20methods,property%20is%20in%20the%20object.
+- https://stackoverflow.com/questions/5765398/whats-the-best-way-to-convert-a-number-to-a-string-in-javascript
+- https://www.w3schools.com/jsref/jsref_switch.asp
+- https://www.w3schools.com/tags/att_input_type_checkbox.asp

index.html

@@ -9,8 +9,7 @@
     <p>Assignment:</p>
     <textarea rows="15" cols="50" id="assignment"></textarea>
     <input type="checkbox" id="algorithm"/>
-    <label for="algorithm">All containers at once?</label>
-
+    <label for="algorithm">Interpret X,Y,Z as Rock Paper Scissor.</label> 
     <p>Answer:</p>
     <div id="answer">Provide input first</div>
     <script src="script.js"></script>

script.js

@@ -1,11 +1,55 @@
 const ASSIGNMENT = 'assignment';
 const ANSWER = 'answer';
 const ALGORITHM_CHECKBOX = 'algorithm';
-const CONTAINER_NULL_CHARACTER=0;
-const INSTRUCTION_FROM='from';
-const INSTRUCTION_MOVE='move';
-const INSTRUCTION_TO='to';
+const ERROR_MESSAGE_NO_SUCH_CHARACTER_IN_RPS = "Non existant character in rock paper scissor game selected: ";
+const ERROR_MESSAGE_TOO_FEW_CHARACTERS_IN_LINE = "Too few characters in line: ";
 const NEWLINE_CHARACTER = '\n';
+const OPTION_LOSE = 'X';
+const OPTION_TIE = 'Y';
+const OPTION_WIN = 'Z';
+
+const RPS = Object.freeze({
+    ROCK: 1,
+    PAPER: 2,
+    SCISSORS: 3,
+
+    /**
+     * Select winning hand for given hand.
+     * @param hand the chosen hand
+     * @return RPS the winning hand
+     */
+    winning_hand: function(hand) {
+        hand++;
+        if(hand > RPS.SCISSORS) {
+            hand = RPS.ROCK;
+        }
+        return hand;
+    },
+
+    /**
+     * Select losing hand for given hand.
+     * @param hand the chosen hand
+     * @return RPS the losing hand
+     */
+    losing_hand: function(hand) {
+        hand--;
+        if(hand < RPS.ROCK) {
+            hand = RPS.SCISSORS;
+        }
+        return hand;
+    }
+});
+const RPS_ALIAS_MAP = Object.freeze({
+    "A": RPS.ROCK,
+    "B": RPS.PAPER,
+    "C": RPS.SCISSORS,
+    "X": RPS.ROCK,
+    "Y": RPS.PAPER,
+    "Z": RPS.SCISSORS,
+})
+const SCORE_LOSE = 0;
+const SCORE_TIE = 3;
+const SCORE_WIN = 6;
 
 /**
  * Main function
@@ -22,8 +66,8 @@ window.onload = function() {
 function calculateAnswer(event) {
   console.info("Calculating answer for input...");
   let assignment = document.getElementById(ASSIGNMENT).value;
-  let allAtOnce = document.getElementById(ALGORITHM_CHECKBOX).checked;
-  let answer = algorithm(assignment, allAtOnce);
+  let interpret_as_rps = document.getElementById(ALGORITHM_CHECKBOX).checked;
+  let answer = algorithm(assignment, interpret_as_rps);
 
   document.getElementById(ANSWER).innerText = answer;
 }
@@ -31,137 +75,117 @@ function calculateAnswer(event) {
 /**
  * Calculate the answer to assignment.
  * @param assignment the input from the assignment.
- * @param allAtOnce should all containers be moved at once.
  * @return string the answer
  */
-function algorithm(assignment, allAtOnce) {
-    let lines = assignment.split(NEWLINE_CHARACTER);
-    let containerPlan = Array.from({length:(lines[0].length+1)/4}, () => [])
+function algorithm(assignment, interpret_as_rps) {
+    let errors = 0;
+    let lines = assignment.trim().split(NEWLINE_CHARACTER);
+    let score = 0;
     console.info("Linecount:" + lines.length);
 
-    let parsec = true;
     for(let i=0; i<lines.length; i++) {
-        if(parsec) {
+        let rps_match = lines[i].replace(/\s/g, ''); // remove all whitespace
+        if(rps_match.length < 2) {
+            console.error(ERROR_MESSAGE_TOO_FEW_CHARACTERS_IN_LINE + i + ", skipped.");
+            errors++;
+            continue;
+        }
 
-            // Parse containers
-            let containerLine = lines[i];
+        // Assign characters from line
+        let opponent_hand = map_hand_character(rps_match[0]); 
+        let player_input = rps_match[1]; 
+        let player_hand = -1;
 
-            // Skip numbers
-            if(containerLine[1] == '1') {
-                parsec = false;
-                i+=1;
-                console.table(containerPlan);
-                continue;
-            }
+        // Validate hand
+        if(opponent_hand<0) {
+            console.error(ERROR_MESSAGE_NO_SUCH_CHARACTER_IN_RPS + rps_match[0] + " for line: " + i);
+            errors++;
+            continue;
+        }
 
-            let containers = parseContainers(containerLine);
-            if(containers == -1) {
-                // invalid containerline
-                // TODO: error
-                console.error("Container parse failure.");
-                continue;
-            }
-
-            // Add containers
-            //console.debug(containers);
-            for(let j=0; j<containers.length; j++) {
-                let container = containers[j];
-                //console.debug(container);
-                if(container != CONTAINER_NULL_CHARACTER) {
-                    //console.debug(j);
-                    //console.debug(containerPlan);
-                    containerPlan[j].push(container);
-                }
-            }
-            //console.table(containerPlan);
+        // How should we interpret input? match_option or Rock Paper Scissors.
+        if(interpret_as_rps) {
+            player_hand = interpret_player_hand_as_rps_input(player_input);
         } else {
-            // Parse instructions
-            let instructionLine = lines[i];
-            let instruction = parseInstruction(instructionLine);
-
-            console.debug(instruction);
-            if(instruction == -1) {
-                // invalid instructionline
-                // TODO: error
-                console.error("Instruction parse failure.");
-                continue;
-            }
-
-            // Execute instruction
-            let movecount=0;
-            if(allAtOnce) {
-                while(instruction.move > 0) {
-                    let container = containerPlan[instruction.from].shift();
-                    containerPlan[instruction.to].unshift(container);
-                    instruction.move--;
-                    movecount++;
-                }
-                console.debug("moved:" + movecount);
-            } else {
-                let splicedContainers = containerPlan[instruction.from].splice(0, instruction.move);
-                containerPlan[instruction.to].unshift(...splicedContainers);
-            }
-
-            //console.table(containerPlan);
+            player_hand = interpret_player_hand_as_match_input(player_input, opponent_hand);
         }
+
+        if(player_hand<0) { // Invalid input
+            console.error(ERROR_MESSAGE_NO_SUCH_CHARACTER_IN_RPS + rps_match[1] + " for line: " + i);
+            errors++;
+            continue;
+        }
+
+        score += rps_result(player_hand, opponent_hand);
     }
 
-    let result="";
-    for(let k=0; k<containerPlan.length; k++) {
-        result += containerPlan[k][0];
+    if(errors > 0) {
+        return errors.toString() + " Error(s) in input, see console for details."
     }
 
-    return "Top containers on the stack are: " + result;
+    return "Player score: " + score;
 }
 
-function parseInstruction(instructionLine) {
-    let instruction={
-        move:0,
-        from:0,
-        to:0,
+/**
+ * Interpret given input for player as a rock paper scissor character.
+ * @param char input the input for hand character (A,B,C,X,Y,Z)
+ * @return the player hand character or -1 if invalid.
+ */
+function interpret_player_hand_as_rps_input(input) {
+    return map_hand_character(input); 
+}
+
+/**
+ * Interpret given input for player as a match option.
+ * @param char input the input for match option (X,Y,Z)
+ * @return the player hand character or -1 if invalid.
+ */
+function interpret_player_hand_as_match_input(input, opponent_hand) {
+    let player_hand = -1;
+    switch (input) {
+        case OPTION_LOSE:
+            player_hand = RPS.losing_hand(opponent_hand);
+            break;
+        case OPTION_WIN:
+            player_hand = RPS.winning_hand(opponent_hand);
+            break;
+        case OPTION_TIE:
+            player_hand = opponent_hand;
+            break;
     }
 
-    instructionLine.replace(/\s/g, ''); // Remove whitespace
-    let fromIndex = instructionLine.indexOf(INSTRUCTION_FROM);
-    let moveIndex = instructionLine.indexOf(INSTRUCTION_MOVE);
-    let toIndex = instructionLine.indexOf(INSTRUCTION_TO);
+    return player_hand;
+}
 
-    // Validate
-    if(fromIndex < 0 || moveIndex < 0 || toIndex < 0) {
-        // Error
+/**
+ * Maps the chosen hand character to 
+ * @param hand_character the chosen character
+ * @return RPS the rock paper scissor hand or -1 if invalid
+ */
+function map_hand_character(hand_character) {
+    if(!(hand_character in RPS_ALIAS_MAP)) {
         return -1;
     }
 
-    // TODO validate check for numbers after indices.
-
-    // Parse
-    instruction.move = parseInt(instructionLine.substring(moveIndex + INSTRUCTION_MOVE.length + 1, fromIndex));
-    instruction.from = parseInt(instructionLine.substring(fromIndex + INSTRUCTION_FROM.length + 1, toIndex)) -1;
-    instruction.to = parseInt(instructionLine.substring(toIndex + INSTRUCTION_TO.length + 1)) -1;
-
-    return instruction;
+    return RPS_ALIAS_MAP[hand_character];
 }
 
-function parseContainers(containerLine) {
-    let containerLineLength = (containerLine.length+1);
-    //console.debug("Parse ContainerLine, length: " + containerLineLength);
-
-    if(!containerLine.includes('[') || !containerLine.includes(']') || containerLineLength % 4 != 0) {
-        return -1;
+/**
+ * Calculate the result of rock paper scissor match
+ * @param RPS player_hand the player's choice
+ * @param RPS opponent_hand the opponent's choice
+ * @return score
+ */
+function rps_result(player_hand, opponent_hand) {
+    let score = 0;
+    if(player_hand == opponent_hand) {
+        score = SCORE_TIE + player_hand;  // TIE
+    } else if(player_hand == RPS.winning_hand(opponent_hand)) {
+        score = SCORE_WIN + player_hand; // WIN
+    } else {
+        score = SCORE_LOSE + player_hand; // LOSE
     }
 
-    let containers = [];
-    for(let i=0; i<containerLineLength; i+=4) {
-        let containerLineSubString = containerLine.substring(i, i+4).trim();
-        let character = containerLineSubString[1];
-        if(containerLineSubString[0] != '[' || containerLineSubString[2] != ']') {
-                // Warning invalid container format
-                // TODO: warning
-        }
-
-        containers.push((!character)? CONTAINER_NULL_CHARACTER: character);
-    }
-    //console.debug(containers);
-
-    return containers;
+    console.debug("score:" + score + ", player: " + player_hand + ", opponent: " + opponent_hand);
+    return score;
 }

style.css

@@ -9,7 +9,6 @@ body {
   textarea {
     display: block;
   }
-  
   #answer {
     color: purple
   }