2f:T4b2,// convert tree-map to boolean map (0/1) deciding whether the tree can be seen from the outside or not isVisible = input.map((line, idxY) => // loo all trees line.map((tree, idxX) => { // loop trees looking east from current tree let visible = true; for (let x = 0; x < idxX; x++) { if (input[idxY][x] >= tree) { visible = false; } } if (visible) { return 1; } // loop trees looking west from current tree visible = true; for (let x = line.length - 1; x > idxX; x--) { if (input[idxY][x] >= tree) { visible = false; } } if (visible) { return 1; } // loop trees looking north from current tree visible = true; for (let y = 0; y < idxY; y++) { if (input[y][idxX] >= tree) { visible = false; } } if (visible) { return 1; } // loop trees looking south from current tree visible = true; for (let y = input.length - 1; y > idxY; y--) { if (input[y][idxX] >= tree) { visible = false; } } if (visible) { return 1; } // if we reached here, we haven't found anything, so return 0 return 0; }) )30:T45e,visibleTrees = input.map((line, idxY) => // loop all trees line.map((tree, idxX) => { let result = 1; // count all trees looking east from current one let cnt = 0; let x = idxX + 1; while (x < line.length && input[idxY][x] < tree) { x++; cnt++; } if (x < line.length) { cnt++; } result *= cnt; // count all trees looking west from current one cnt = 0; x = idxX - 1; while (x >= 0 && input[idxY][x] < tree) { x--; cnt++; } if (x >= 0) { cnt++; } result *= cnt; // count all trees looking north from current one cnt = 0; let y = idxY + 1; while (y < input.length && input[y][idxX] < tree) { y++; cnt++; } if (y < input.length) { cnt++; } result *= cnt; // count all trees looking south from current one cnt = 0; y = idxY - 1; while (y >= 0 && input[y][idxX] < tree) { y--; cnt++; } if (y >= 0) { cnt++; } result *= cnt; // return product of the 4 values found in all directions return result; }) )31:[{"id":"51a9de4214b3ee9376f5f4bffaeab814b8851bd80d097582e0c5c696f03c4158c5b7d473384c21b10c8657c7a59595936f064d4ef7fa2fb84b839c7f6d9025a8","href":"https://static.observableusercontent.com/files/51a9de4214b3ee9376f5f4bffaeab814b8851bd80d097582e0c5c696f03c4158c5b7d473384c21b10c8657c7a59595936f064d4ef7fa2fb84b839c7f6d9025a8","name":"input.txt","type":"text/plain","lastModified":1670527950034.195,"size":9900}] 2d:{"title":"Day 8 - Treetop Tree House","cells":[{"id":0,"value":"# Day 8 - [Treetop Tree House](https://adventofcode.com/2022/day/8)","pinned":false,"hidden":false,"mode":"md"},{"id":3,"value":"inputs0 = `30373\n25512\n65332\n33549\n35390`","pinned":true,"hidden":false,"mode":"ojs"},{"id":24,"value":"inputs = FileAttachment(\"input.txt\").text()","pinned":true,"hidden":false,"mode":"ojs"},{"id":7,"value":"// parse inputs into 2D map of heights\ninput = inputs.split(\"\\n\").map((line) => line.split(\"\"))","pinned":true,"hidden":false,"mode":"ojs"},{"id":78,"value":"// print tree map in ASCII style\nprintMap = (result) => {\n return html`\n

${result\n      .map((line) => line.map((el) => (el > 0 ? \"*\" : \" \")).join(\"\"))\n      .join(\"\\n\")}

\n `;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":199,"value":"// visualize input map as heatmap\nplotTrees = (treeMap, title) =>\n Plot.plot({\n caption: title,\n width: 600,\n height: 600,\n padding: 0.1,\n grid: true,\n x: {\n axis: false\n },\n y: {\n axis: false\n },\n color: {\n type: \"diverging\"\n },\n marks: [\n Plot.cell(\n treeMap\n .map((line, y) =>\n line.map((el, x) => {\n return { x: x, y: y, val: el };\n })\n )\n .flat(1),\n {\n x: \"x\",\n y: \"y\",\n fill: \"val\",\n rx: 20\n }\n )\n ]\n })","pinned":true,"hidden":false,"mode":"ojs"},{"id":201,"value":"plotTrees(input, \"tree-map knput\")","pinned":true,"hidden":false,"mode":"ojs"},{"id":74,"value":"## Part 1","pinned":false,"hidden":false,"mode":"md"},{"id":9,"value":"$2f","pinned":true,"hidden":false,"mode":"ojs"},{"id":20,"value":"// sum-up all visible trees (i.e. having value >0)\nresult1 = isVisible.reduce(\n (acc1, curr1) => acc1 + curr1.reduce((acc2, curr2) => acc2 + curr2, 0),\n 0\n)","pinned":true,"hidden":false,"mode":"ojs"},{"id":81,"value":"// show the visible trees as (ASCII) map\n//printMap(isVisible)","pinned":true,"hidden":false,"mode":"ojs"},{"id":207,"value":"plotTrees(isVisible, \"visible trees from the outside\")","pinned":true,"hidden":false,"mode":"ojs"},{"id":76,"value":"## Part 2","pinned":false,"hidden":false,"mode":"md"},{"id":28,"value":"$30","pinned":true,"hidden":false,"mode":"ojs"},{"id":65,"value":"// find the maximum value\nresult2 = visibleTrees.reduce(\n (acc1, curr1) =>\n Math.max(\n acc1,\n curr1.reduce((acc2, curr2) => Math.max(acc2, curr2), 0)\n ),\n 0\n)","pinned":true,"hidden":false,"mode":"ojs"},{"id":210,"value":"plotTrees(visibleTrees, \"number of seeable trees\")","pinned":true,"hidden":false,"mode":"ojs"}],"files":"$W31","stdlib":"1","titling":"auto"}