Initial working commit

2022-12-11 12:44:35 +01:00
4 changed files with 122 additions and 8 deletions
--- a/README.md
+++ b/README.md
@@ -1 +1,8 @@
-This repository contains answers to the assignments of Advent of Coding 2022
+# 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://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
@@ -8,6 +8,8 @@
  <body>
    <p>Assignment:</p>
    <textarea rows="15" cols="50" id="assignment"></textarea>
+    <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
@@ -1,5 +1,6 @@
 const ASSIGNMENT = 'assignment';
 const ANSWER = 'answer';
+const ALGORITHM_CHECKBOX = 'algorithm';
 const NEWLINE_CHARACTER = '\n';

 /**
@@ -7,6 +8,7 @@ const NEWLINE_CHARACTER = '\n';
 */
 window.onload = function () {
  document.getElementById(ASSIGNMENT).addEventListener("input", calculateAnswer);
+  document.getElementById(ALGORITHM_CHECKBOX).addEventListener("click", calculateAnswer);
 }

 /**
@@ -15,7 +17,9 @@ 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 getHighestScenicScore = document.getElementById(ALGORITHM_CHECKBOX).checked;
+  let answer = algorithm(assignment, getHighestScenicScore);

  document.getElementById(ANSWER).innerText = answer;
 }
@@ -25,9 +29,106 @@ function calculateAnswer(event) {
 * @param assignment the input from the assignment.
 * @return string the answer
 */
-function algorithm(assignment) {
+function algorithm(assignment, getHighestScenicScore) {
  let lines = assignment.trim().split(NEWLINE_CHARACTER);
  console.info("Linecount:" + lines.length);

-    // TODO: implement assignment
+  let visibleTreeCount = 0;
+  let highestScenicScore = 0;
+
+  for (let i = 0; i < lines.length; i++) {
+    let row = lines[i].trim();
+
+    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;
+      }
+
+      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--;
+      }
+
+      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;
+}
+
+function walkColumnCount(height, index, rowIndex, column) {
+  return walkCount(height, index, column, false, rowIndex);
+}
+
+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;
+  }
+
+  direction = direction / Math.abs(direction);
+
+  // Edge reached
+  if ((direction < 0 && index <= 0) || (direction > 0 && index >= line.length - 1)) {
+    return (count == undefined) ? true : count;
+  }
+
+  let nextIndex = index + direction;
+  let nextHeightCharacter = (isRow) ? line.charAt(nextIndex) : line[nextIndex].trim().charAt(rowIndex);
+  let nextHeight = parseInt(nextHeightCharacter);
+
+  if (isNaN(height) || isNaN(nextHeightCharacter)) {
+    console.error("Invalid height found, height:" + height + ", nextHeight: " + nextHeightCharacter);
+    return -1;
+  }
+
+  if (height <= nextHeight) {
+    if (count == undefined)
+      return false;
+    return count + 1;
+  }
+
+  return __walkHelper(height, nextIndex, line, isRow, direction, rowIndex, (count !=undefined)? count + 1 : undefined);
 }
--- a/style.css
+++ b/style.css
@@ -6,6 +6,10 @@ body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  }
  
+  textarea {
+    display: block;
+  }
+
  #answer {
    color: purple
  }