Initial working commit

2022-12-11 12:44:35 +01:00
4 changed files with 102 additions and 125 deletions
--- a/README.md
+++ b/README.md
@@ -1,12 +1,8 @@
-# Advent of Code 2022 - Assignment3 javascript solution
-This problem is all about searching for duplicates in strings. The solution is implemented using slice to split the string in half. 
-The priority is retrieved using the ASCII charcode character for convienence. How to retrieve inputs differs between part1 and 2, therefore a checkbox is provided to toggle between different parsing methods.
+# Advent of Code 2022 - Assignment8 javascript
+## Description
+This problem is all about walking through a grid. In this solution, we look through an entire column and row until we find a node with height <= height.

 ## References
- https://stackoverflow.com/questions/94037/convert-character-to-ascii-code-in-javascript
- https://stackoverflow.com/questions/20474257/split-string-into-two-parts
- https://www.folkstalk.com/2022/10/find-common-characters-in-two-strings-javascript-with-code-examples.html
- https://stackoverflow.com/questions/351409/how-to-append-something-to-an-array
- https://stackoverflow.com/questions/9862761/how-to-check-if-character-is-a-letter-in-javascript
- https://stackoverflow.com/questions/1966476/how-can-i-process-each-letter-of-text-using-javascript
- https://www.w3schools.com/js/js_arrays.asp
+- https://www.w3schools.com/jsref/jsref_charat.asp
+- https://stackabuse.com/javascript-check-if-variable-is-a-number/
+- https://www.w3schools.com/jsref/jsref_abs.asp
--- a/index.html
+++ b/index.html
@@ -8,8 +8,8 @@
  <body>
    <p>Assignment:</p>
    <textarea rows="15" cols="50" id="assignment"></textarea>
-    <input type="checkbox" id="algorithm"/>
-    <label for="algorithm">Solution by compartiment.</label> 
+    <input type="checkbox" id="algorithm" />
+    <label for="algorithm">Highest scenic score?</label>

    <p>Answer:</p>
    <div id="answer">Provide input first</div>
--- a/script.js
+++ b/script.js
@@ -1,16 +1,12 @@
 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';

 /**
 * Main function
 */
-window.onload = function() {
+window.onload = function () {
  document.getElementById(ASSIGNMENT).addEventListener("input", calculateAnswer);
  document.getElementById(ALGORITHM_CHECKBOX).addEventListener("click", calculateAnswer);
 }
@@ -22,8 +18,8 @@ window.onload = function() {
 function calculateAnswer(event) {
  console.info("Calculating answer for input...");
  let assignment = document.getElementById(ASSIGNMENT).value;
-  let byCompartiments = document.getElementById(ALGORITHM_CHECKBOX).checked;
-  let answer = algorithm(assignment, byCompartiments);
+  let getHighestScenicScore = document.getElementById(ALGORITHM_CHECKBOX).checked;
+  let answer = algorithm(assignment, getHighestScenicScore);

  document.getElementById(ANSWER).innerText = answer;
 }
@@ -33,121 +29,106 @@ function calculateAnswer(event) {
 * @param assignment the input from the assignment.
 * @return string the answer
 */
-function algorithm(assignment, byCompartiments) {
-    let priorityScoreSum = 0;
+function algorithm(assignment, getHighestScenicScore) {
  let lines = assignment.trim().split(NEWLINE_CHARACTER);
  console.info("Linecount:" + lines.length);

-    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
+  let visibleTreeCount = 0;
+  let highestScenicScore = 0;

-        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, '')];
-        }
+  for (let i = 0; i < lines.length; i++) {
+    let row = lines[i].trim();

-        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);
+    for (let j = 0; j < row.length; j++) {
+      if (i <= 0 || i >= lines.length - 1 || j <= 0 || j >= row.length - 1) { // Edge node
+        //console.debug("Edge node found.");
+        visibleTreeCount++;
        continue;
      }
-        priorityScoreSum += priorityScore;
+
+      let height = parseInt(lines[i].charAt(j));
+      if (!walkRowVisible(height, j, row) && !walkColumnVisible(height, i, j, lines)) {
+        console.log("Found invisible tree, height:" + height + ", i:" + i + ", j:" + j);
+        visibleTreeCount--;
      }

-    return "SUM priorityscore: " + priorityScoreSum;
+      if (getHighestScenicScore) {
+        let scenicScore = walkRowCount(height, j, row) * walkColumnCount(height, i, j, lines);
+        if (scenicScore > highestScenicScore) {
+          console.debug("Found new highest scenic score: " + scenicScore);
+          highestScenicScore = scenicScore;
+        }
+      }
+
+      // Tree is on edge.
+      visibleTreeCount++;
+    }
+  }
+
+  if (getHighestScenicScore) {
+    return "Highest scenic score: " + highestScenicScore;
+  }
+
+  return "Amount of visible trees in the grid: " + visibleTreeCount;
 }

-/**
- * 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;
+function walkColumnCount(height, index, rowIndex, column) {
+  return walkCount(height, index, column, false, rowIndex);
 }

-/**
- * 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) {
+function walkRowCount(height, index, row) {
+  return walkCount(height, index, row, true, -1);
+}
+
+function walkColumnVisible(height, index, rowIndex, column) {
+  return walkVisible(height, index, column, false, rowIndex);
+}
+
+function walkRowVisible(height, index, row) {
+  return walkVisible(height, index, row, true, -1);
+}
+
+function walkCount(height, index, line, isRow, rowIndex) {
+  let visibleLeftCount = __walkHelper(height, index, line, isRow, -1, rowIndex, 0);
+  let visibleRightCount = __walkHelper(height, index, line, isRow, 1, rowIndex, 0);
+
+  return visibleLeftCount * visibleRightCount;
+}
+
+function walkVisible(height, index, line, isRow, rowIndex) {
+  let visibleLeft = __walkHelper(height, index, line, isRow, -1, rowIndex);
+  let visibleRight = __walkHelper(height, index, line, isRow, 1, rowIndex);
+
+  return visibleLeft || visibleRight;
+}
+
+function __walkHelper(height, index, line, isRow, direction, rowIndex, count) {
+  if (direction == 0) {
+    console.error("Invalid direction 0 in __walkhelper");
    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);
+  direction = direction / Math.abs(direction);
+
+  // Edge reached
+  if ((direction < 0 && index <= 0) || (direction > 0 && index >= line.length - 1)) {
+    return (count == undefined) ? true : count;
  }

-        if(duplicate) {
-            console.debug("Found duplicate: " + item);
-            return item;
-        }
-    }
-}
+  let nextIndex = index + direction;
+  let nextHeightCharacter = (isRow) ? line.charAt(nextIndex) : line[nextIndex].trim().charAt(rowIndex);
+  let nextHeight = parseInt(nextHeightCharacter);

-/**
- * 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 ) {
+  if (isNaN(height) || isNaN(nextHeightCharacter)) {
+    console.error("Invalid height found, height:" + height + ", nextHeight: " + nextHeightCharacter);
    return -1;
  }

-    if(character == uppercase) { // Switch results for upper and lowercase characters
-        result -= CHARCODE_UPPER_CORRECTION;
-        character = lowercase;
-    } else {
-        character = uppercase;
+  if (height <= nextHeight) {
+    if (count == undefined)
+      return false;
+    return count + 1;
  }

-    result += character.charCodeAt() - CHARCODE_START;
-
-    return result;
+  return __walkHelper(height, nextIndex, line, isRow, direction, rowIndex, (count !=undefined)? count + 1 : undefined);
 }