Solution for assignment3.

script.js

@@ -1,5 +1,10 @@
 const ASSIGNMENT = 'assignment';
 const ANSWER = 'answer';
+const ALGORITHM_CHECKBOX = 'algorithm';
+const CHARCODE_START=64;
+const CHARCODE_UPPER_CORRECTION=6;
+const ERROR_MESSAGE_INVALID_INPUT_SIZE = "Invalid input size, should be higher than 2 for: ";
+const ERROR_MESSAGE_INVALID_ITEM_CHARACTER = "Invalid item character found: ";
 const NEWLINE_CHARACTER = '\n';
 
 /**
@@ -7,6 +12,7 @@ const NEWLINE_CHARACTER = '\n';
  */
 window.onload = function() {
     document.getElementById(ASSIGNMENT).addEventListener("input", calculateAnswer);
+    document.getElementById(ALGORITHM_CHECKBOX).addEventListener("click", calculateAnswer);
 }
 
 /**
@@ -15,7 +21,9 @@ window.onload = function() {
  */
 function calculateAnswer(event) {
   console.info("Calculating answer for input...");
-  let answer = algorithm(event.target.value);
+  let assignment = document.getElementById(ASSIGNMENT).value;
+  let byCompartiments = document.getElementById(ALGORITHM_CHECKBOX).checked;
+  let answer = algorithm(assignment, byCompartiments);
 
   document.getElementById(ANSWER).innerText = answer;
 }
@@ -25,9 +33,121 @@ function calculateAnswer(event) {
  * @param assignment the input from the assignment.
  * @return string the answer
  */
-function algorithm(assignment) {
+function algorithm(assignment, byCompartiments) {
+    let priorityScoreSum = 0;
     let lines = assignment.trim().split(NEWLINE_CHARACTER);
     console.info("Linecount:" + lines.length);
 
-    // TODO: implement assignment
+    let increment = (byCompartiments)? 1:3;
+    for(let i=0; i<lines.length; i+=increment) {
+        let inputs = [];
+        let rucksack = lines[i].replace(/\s/g, ''); // Remove whitespace
+
+        if(byCompartiments) {
+            let compartiment1 = rucksack.slice(0, rucksack.length/2);
+            let compartiment2 = rucksack.slice(rucksack.length/2);
+            inputs = [compartiment1, compartiment2];
+        } else {
+            inputs = [rucksack, lines[i+1].replace(/\s/g, ''), lines[i+2].replace(/\s/g, '')];
+        }
+
+        let duplicate = getDuplicateCharacter(inputs);
+        if(duplicate < 0) {
+            console.error(ERROR_MESSAGE_INVALID_INPUT_SIZE + inputs + " on line: " + i);
+        }
+
+        let priorityScore = getPriorityScore(duplicate);
+        if(priorityScore < 0) {
+            console.error(ERROR_MESSAGE_INVALID_ITEM_CHARACTER + duplicate + " on line: " + i);
+            continue;
+        }
+        priorityScoreSum += priorityScore;
+    }
+
+    return "SUM priorityscore: " + priorityScoreSum;
+}
+
+/**
+ * Calculate the answer to assignment.
+ * @param assignment the input from the assignment.
+ * @return string the answer
+ */
+ function algorithm1(assignment) {
+    let priorityScoreSum = 0;
+    let lines = assignment.trim().split(NEWLINE_CHARACTER);
+    console.info("Linecount:" + lines.length);
+
+    for(let i=0; i<lines.length; i++) {
+        let rucksack = lines[i].replace(/\s/g, ''); // Remove whitespace
+        let compartiment1 = rucksack.slice(0, rucksack.length/2);
+        let compartiment2 = rucksack.slice(rucksack.length/2);
+
+        console.debug("Check rucksack" + i, ": " + rucksack + " \n with compartiment1: " + compartiment1 + "\n and compartiment2: " + compartiment2);
+        
+        for(item of compartiment2) {
+            if(compartiment1.includes(item)) {
+                console.debug("Found duplicate: " + item + " in rucksack" + i);
+                let priorityScore = getPriorityScore(item);
+                if(priorityScore < 0) {
+                    console.error(ERROR_MESSAGE_INVALID_ITEM_CHARACTER + item + " on line: " + i);
+                    continue;
+                }
+                priorityScoreSum += priorityScore;
+                break;
+            }
+        }
+    }
+
+    return "SUM priorityscore: " + priorityScoreSum;
+}
+
+/**
+ * Find duplicate character in inputs.
+ * @param string[] inputs the inputs to find duplicates in. 
+ * @return char the duplicate character
+ */
+function getDuplicateCharacter(inputs) {
+    console.debug("Checking inputs: " + inputs);
+    if(inputs.length < 2) {
+        return -1;
+    }
+
+    for(let item of inputs[0]) {
+        let duplicate = true
+        for(let j=1; j<inputs.length; j++) {
+            duplicate = duplicate && inputs[j].includes(item);
+        }
+
+        if(duplicate) {
+            console.debug("Found duplicate: " + item);
+            return item;
+        }
+    }
+}
+
+/**
+ * Returns priorityscore for given character.
+ * @param char character the character
+ * @return int the priorityscore for character or -1 if invalid 
+ */
+function getPriorityScore(character) {
+    let result=0;
+    let uppercase = character.toUpperCase();
+    let lowercase = character.toLowerCase();
+    
+    // validate character
+    if( uppercase == lowercase ) {
+        return -1;
+    }
+    
+    if(character == uppercase) { // Switch results for upper and lowercase characters
+        result -= CHARCODE_UPPER_CORRECTION;
+        character = lowercase;
+    } else {
+        character = uppercase;
+    }
+
+    result += character.charCodeAt() - CHARCODE_START;
+
+    return result;
 }