2024 day 10 part 2 in javascript

2024/10/example.txt

@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732

2024/10/input.txt

@@ -0,0 +1,58 @@
+5678970120787667809876787651450321789810165432234561012345
+4301787431296556912765698540341410786728765501103676545434
+3212896594365443213454501231232545695439154610898387656946
+4307885785872337801653215432545694321089043781763296047877
+5456934576901236998740126721694787899676112891054102137898
+4327825676210365485035432830780146788765208982567873223703
+1012010789301345304126701910567235623654367643432984012612
+9887652105401253213239878323458945514545106543221265698543
+6798943766798760560145569850179876408763215456100896787432
+5212237854899621056776457763287654309854580367018701656501
+4302108983014552345889308954390101218345691278929632540987
+8921321212123467496973217654321010101210782987834541231236
+7010450908765658787210106563898110567623458906543210340145
+6524567849434349872323293478967223408988967217890107459054
+5433008956721238721494782566554310510177654394345498768765
+8942112349810101430585691057431214321287656783216321659056
+9853523658901233549674541008120109450392345654307010123141
+6765434567890312678234432219078218765431874309458927034230
+1034323450765403510165498348569341016210967218567898985541
+4125614321877654523276327653414452547893458967898769876632
+3210701234988347678987014512103963458982105450745601896781
+4678890215679298689898101105432878967821123301234312765890
+5469810309100198776543239416001263456710054210126543454323
+6954323458210789743987678327122452349821269329237632670110
+7856542167345679812310565498214301265430178778748911789224
+3067630018901256701423457012303210178923476565652100654343
+2188921078872345690501298989452121089012383418983434334534
+3298934569863418987632367898763011298234592307894521025676
+0387650101678507876753456501014980347105681016765601210787
+1456343212589216909865401432325671256501789823454782309898
+2341067823410365419872316543234560787432328987123495434321
+8932058934321474321891027652101765698543212656016596521030
+7634149965430589890765438984989854321692303443067787676543
+4543232876787672763210567823870143430781054512198971980612
+4687601045298101454569498014561034231278766503456890121701
+3894523432101212343278307601432120140389107652107765439890
+2183410589043239852101212587347899655473298940998987610141
+1012398679650126760120103496256978796554567831876898543234
+0310487778743245679833210145107878987143278722365687650125
+1223456899012632988744103230123217610012189013451232105676
+8346543456598701279655654389874306526323076567600345694789
+9857812347405654210346969210165435435414105458912256783238
+6768901098312343981237878301456521056905912345863109890104
+0345650101232107834369765412347678167876801056874223454323
+1278761321943456125078098943678999101210760767985214567910
+2109874430854534076165107834567783212323458898876307698876
+3436543561763325689234256623478654323212789954343298714565
+4567612675610118763240345510569823434101652765210134503443
+5698203984323709454121245432234712345612501897898325612652
+6782100112345890365039876101165601016780432101107210726761
+6783078201076761276321276543036523239891569232216874835890
+5894569345987457889430389236543210145652678740125965934701
+6784578896590356996321298107012301276743245656734014821012
+5693678787101243987654301058905434985890130543876523498763
+4542109843262012276019012765676125673981021982923434549854
+3432101257876540145328943894387089012832123671019323676345
+4309210369901234239457654703298976326721034501208710789234
+3218765478710123378765645612107845435434345212345621678101

2024/10/solution.js

@@ -0,0 +1,55 @@
+
+const input = (await Bun.file("input.txt").text()).trim()
+
+const rows = [[]];
+
+const trailheads = [];
+
+for (let i = 0, x = 0, y = 0; i < input.length; i++) {
+  if (input[i] == "\n") {
+    rows.push([]);
+    y++;
+    x = 0;
+    continue;
+  }
+  const alt = parseInt(input[i]);
+  rows[y].push(alt);
+  if (alt == 0) {
+    trailheads.push({x,y})
+  }
+  x++;
+}
+
+const summitChart = Array.from({length: rows.length}, () => Array.from({length: rows.length}, () => (new Set())))
+
+function findSummits({x, y}) {
+  if (summitChart[y][x].size > 0) {
+    return summitChart[y][x]
+  }
+  if (rows[y][x] == 9) {
+    summitChart[y][x].add(x + y * rows.length)
+    return summitChart[y][x]
+  }
+  if (x != 0               && rows[y][x-1] - rows[y][x] == 1) {
+    summitChart[y][x] = summitChart[y][x].union(findSummits({y, x: x - 1}))
+  }
+  if (x != rows.length - 1 && rows[y][x+1] - rows[y][x] == 1) {
+    summitChart[y][x] = summitChart[y][x].union(findSummits({y, x: x + 1}))
+  }
+  if (y != 0               && rows[y-1][x] - rows[y][x] == 1) {
+    summitChart[y][x] = summitChart[y][x].union(findSummits({y: y-1, x}))
+  }
+  if (y != rows.length - 1 && rows[y+1][x] - rows[y][x] == 1) {
+    summitChart[y][x] = summitChart[y][x].union(findSummits({y: y+1, x}))
+  }
+  return summitChart[y][x]
+}
+
+let sum = 0;
+for (const trailhead of trailheads) {
+  const summits = findSummits(trailhead)
+  sum += summits.size
+}
+
+console.log(sum)
+

2024/10/solution2.js

@@ -0,0 +1,55 @@
+
+const input = (await Bun.file("input.txt").text()).trim()
+
+const rows = [[]];
+
+const trailheads = [];
+
+for (let i = 0, x = 0, y = 0; i < input.length; i++) {
+  if (input[i] == "\n") {
+    rows.push([]);
+    y++;
+    x = 0;
+    continue;
+  }
+  const alt = parseInt(input[i]);
+  rows[y].push(alt);
+  if (alt == 0) {
+    trailheads.push({x,y})
+  }
+  x++;
+}
+
+const summitChart = Array.from({length: rows.length}, () => Array.from({length: rows.length}, () => ([])))
+
+function findSummits({x, y}) {
+  if (summitChart[y][x].length > 0) {
+    return summitChart[y][x]
+  }
+  if (rows[y][x] == 9) {
+    summitChart[y][x].push(x + y * rows.length)
+    return summitChart[y][x]
+  }
+  if (x != 0               && rows[y][x-1] - rows[y][x] == 1) {
+    summitChart[y][x].push(...findSummits({y, x: x - 1}))
+  }
+  if (x != rows.length - 1 && rows[y][x+1] - rows[y][x] == 1) {
+    summitChart[y][x].push(...findSummits({y, x: x + 1}))
+  }
+  if (y != 0               && rows[y-1][x] - rows[y][x] == 1) {
+    summitChart[y][x].push(...findSummits({y: y-1, x}))
+  }
+  if (y != rows.length - 1 && rows[y+1][x] - rows[y][x] == 1) {
+    summitChart[y][x].push(...findSummits({y: y+1, x}))
+  }
+  return summitChart[y][x]
+}
+
+let sum = 0;
+for (const trailhead of trailheads) {
+  const summits = findSummits(trailhead)
+  sum += summits.length
+}
+
+console.log(sum)
+