Assignment2 algorithm solution.

2022-12-04 20:53:01 +01:00
4 changed files with 167 additions and 29 deletions
--- a/README.md
+++ b/README.md
@@ -1,5 +1,12 @@
-# Advent of Code 2022 - Assignment6_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://stackoverflow.com/questions/28207610/checking-if-the-characters-in-a-string-are-all-unique
+- 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
--- a/index.html
+++ b/index.html
@@ -8,9 +8,8 @@
  <body>
    <p>Assignment:</p>
    <textarea rows="15" cols="50" id="assignment"></textarea>
-    <input type="checkbox" id="algorithm" />
-    <label for="algorithm">Search for message marker?</label>
-    
+    <input type="checkbox" id="algorithm"/>
+    <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>
--- a/script.js
+++ b/script.js
@@ -1,16 +1,62 @@
 const ASSIGNMENT = 'assignment';
 const ANSWER = 'answer';
 const ALGORITHM_CHECKBOX = 'algorithm';
-const MARKER_DISTINCT_CHARACTERS = 4;
-const MESSAGE_DISTINCT_CHARACTERS = 14;
+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
 */
 window.onload = function() {
-  document.getElementById(ASSIGNMENT).addEventListener("input", calculateAnswer);
-  document.getElementById(ALGORITHM_CHECKBOX).addEventListener("click", calculateAnswer);
+    document.getElementById(ASSIGNMENT).addEventListener("input", calculateAnswer);
+    document.getElementById(ALGORITHM_CHECKBOX).addEventListener("click", calculateAnswer);
 }

 /**
@@ -20,8 +66,8 @@ window.onload = function() {
 function calculateAnswer(event) {
  console.info("Calculating answer for input...");
  let assignment = document.getElementById(ASSIGNMENT).value;
-  let distinctCharacters = (document.getElementById(ALGORITHM_CHECKBOX).checked)? MESSAGE_DISTINCT_CHARACTERS: MARKER_DISTINCT_CHARACTERS;
-  let answer = algorithm(assignment, distinctCharacters);
+  let interpret_as_rps = document.getElementById(ALGORITHM_CHECKBOX).checked;
+  let answer = algorithm(assignment, interpret_as_rps);

  document.getElementById(ANSWER).innerText = answer;
 }
@@ -31,28 +77,115 @@ function calculateAnswer(event) {
 * @param assignment the input from the assignment.
 * @return string the answer
 */
-function algorithm(assignment, distinctCharacters) {
-    let signal = assignment.trim();
-    let marker = assignment.substring(0,distinctCharacters);
+function algorithm(assignment, interpret_as_rps) {
+    let errors = 0;
+    let lines = assignment.trim().split(NEWLINE_CHARACTER);
+    let score = 0;
+    console.info("Linecount:" + lines.length);

-    for(let i=distinctCharacters; i<signal.length; i++) {
-      if(containsDistinctCharacters(marker)) {
-        console.debug("Found marker after:" + i + " characters");
-        return "Marker found after processing: " + i + " characters.";
-      }
+    for(let i=0; i<lines.length; i++) {
+        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;
+        }

-      marker = marker.substring(1, distinctCharacters) + assignment[i];
+        // Assign characters from line
+        let opponent_hand = map_hand_character(rps_match[0]); 
+        let player_input = rps_match[1]; 
+        let player_hand = -1;
+
+        // Validate hand
+        if(opponent_hand<0) {
+            console.error(ERROR_MESSAGE_NO_SUCH_CHARACTER_IN_RPS + rps_match[0] + " for line: " + i);
+            errors++;
+            continue;
+        }
+
+        // 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 {
+            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);
    }

-    return "No marker found.";
+    if(errors > 0) {
+        return errors.toString() + " Error(s) in input, see console for details."
+    }
+
+    return "Player score: " + score;
 }

 /**
- * Check if string only contains distinct characters.
- * @param String string the string to check
- * @return true, if string contains only distinct characters
+ * 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 containsDistinctCharacters(string) {
-  console.debug("Check marker: " + string);
-  return new Set(string).size == string.length;
+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;
+    }
+
+    return player_hand;
+}
+
+/**
+ * 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;
+    }
+
+    return RPS_ALIAS_MAP[hand_character];
+}
+
+/**
+ * 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
+    }
+
+    console.debug("score:" + score + ", player: " + player_hand + ", opponent: " + opponent_hand);
+    return score;
 }
--- a/style.css
+++ b/style.css
@@ -9,7 +9,6 @@ body {
  textarea {
    display: block;
  }
-  
  #answer {
    color: purple
  }