feat(2020-day-11): iterate seating with visibility rules

for part 2

Author: developher-net

2020/day-11/seating.js

@@ -10,7 +10,35 @@ const format = (seatMap) => {
 }
 
 const occupiedLineOfSite = ({ x, y, seatMap }) => {
+  let occupied = 0
+  const look = ({ lookX, lookY, dirX, dirY }) => {
+    if (lookY < 0 || lookY >= seatMap.length) {
+      // exceeded rows space
+      return 'x'
+    }
+    if (lookX < 0 || lookX >= seatMap[0].length) {
+      // exceeded column space
+      return 'x'
+    }
+    // Find the first seat in the direction, recursively
+    if (seatMap[lookY][lookX] !== '.') {
+      return seatMap[lookY][lookX]
+    }
+
+    // Recursively look in the next seat in this direction
+    return look({ lookX: lookX + dirX, lookY: lookY + dirY, dirX, dirY })
+  }
 
+  // 8 compass point directions
+  for (let dirX = -1; dirX <= 1; dirX++) {
+    for (let dirY = -1; dirY <= 1; dirY++) {
+      if (look({ lookX: x + dirX, lookY: y + dirY, dirX, dirY }) === '#') {
+        occupied++
+      }
+    }
+  }
+
+  return occupied
 }
 
 const occupiedNearby = ({ x, y, seatMap }) => {
@@ -41,7 +69,7 @@ const advance = (seatMap, rules) => {
   })
 }
 
-const update = ({ x, y, seatMap, rules }) => {
+const update = ({ x, y, seatMap, rules = 'proximity' }) => {
   let leaveThreshold = 4
   let processor = occupiedNearby
   if (rules === 'visibility') {

2020/day-11/seating.test.js

@@ -75,7 +75,19 @@ L.#.L..#..
 #.#L#L#.##`
 )
 
-const testDataPart2 = testData.slice(0, 2)
+const testDataPart2 = [testData[0]]
+testDataPart2.push(
+`#.##.##.##
+#######.##
+#.#.#..#..
+####.##.##
+#.##.##.##
+#.#####.##
+..#.#.....
+##########
+#.######.#
+#.#####.##`
+)
 testDataPart2.push(
 `#.LL.LL.L#
 #LLLLLL.LL
@@ -171,14 +183,14 @@ describe('--- Day 11: Seating System ---', () => {
 .........
 #........
 ...#.....`
-        expect(occupiedLineOfSite({ x: 1, y: 1, seatMap: data })).to.equal(8)
+        expect(occupiedLineOfSite({ x: 3, y: 4, seatMap: parse(data) })).to.equal(8)
       })
       it('cannot see occupied seats past an available seat', () => {
         const data =
 `.............
 .L.L.#.#.#.#.
 .............`
-        expect(occupiedLineOfSite({ x: 3, y: 4, seatMap: data })).to.equal(0)
+        expect(occupiedLineOfSite({ x: 1, y: 1, seatMap: parse(data) })).to.equal(0)
       })
       it('can look in all compass directions', () => {
         const data =
@@ -189,21 +201,22 @@ describe('--- Day 11: Seating System ---', () => {
 ##...##
 #.#.#.#
 .##.##.`
-        expect(occupiedLineOfSite({ x: 3, y: 3, seatMap: data })).to.equal(0)
+        expect(occupiedLineOfSite({ x: 3, y: 3, seatMap: parse(data) })).to.equal(0)
       })
     })
     describe('advance()', () => {
       it('accepts visibility rules instead of proximity', () => {
         const results = testDataPart2.map((data) => {
           return format(
             advance(
-              parse(data), 'visible'
+              parse(data), 'visibility'
             )
           )
         })
 
         for (let x = 1; x < testDataPart2.length; x++) {
           console.debug('Step', x)
+          console.debug(results[x - 1])
           expect(results[x - 1]).to.equal(testDataPart2[x])
         }
         const finalOccupancy = (results[results.length - 1].match(/#/g) || []).length