feat(2021-day-05): map orthagonal lines for hydrothermal vents

developher-net · developher-net · commit a20facaa15c3 · 2021-12-14T01:39:16.000-08:00
diff --git a/2021/day-05/vents.js b/2021/day-05/vents.js
@@ -0,0 +1,67 @@
+/**
+ *
+ * @param {*} data Existing coordinate data
+ * @param {*} x1 start of line horizontal point
+ * @param {*} y1 start of line vertical point
+ * @param {*} x2 end of line horizontal point
+ * @param {*} y2 end of line vertical point
+ * @returns
+ */
+const chartLine = (data, x1, y1, x2, y2) => {
+  let x = x1
+  let y = y1
+  if (y1 === y2) {
+    // chart horizontal line
+    console.debug(`Drawing horizontal line ${x1},${y1} to ${x2},${y2}`)
+    const xDir = (x2 > x1) ? 1 : -1
+    while (x !== x2) {
+      data[y][x]++
+      x += xDir
+    }
+    data[y][x]++ // coordinates are inclusive
+  } else if (x1 === x2) {
+    // chart vertical line
+    console.debug(`Drawing vertical line ${x1},${y1} to ${x2},${y2}`)
+    const yDir = (y2 > y1) ? 1 : -1
+    while (y !== y2) {
+      data[y][x]++
+      y += yDir
+    }
+    data[y][x]++ // coordinates are inclusive
+  } else {
+    console.debug(`Skipping diagonal line ${x1},${y1} to ${x2},${y2}`)
+  }
+  return data
+}
+
+/**
+ * Creates a visible map from the data
+ * @param {*} data
+ * @returns string
+ */
+const render = (data) => {
+  return data
+    .map((row) => row.join(''))
+    .join('\n')
+    .replace(/0/gi, '.')
+}
+
+/**
+ * Parses the provided data rules into useable lines
+ * @param string data
+ * @returns Array
+ */
+const parseLines = (data) => {
+  return data.split('\n')
+    .map(
+      (row) => row.replace(' -> ', ',')
+        .split(',')
+        .map((val) => parseInt(val))
+    )
+}
+
+module.exports = {
+  render,
+  chartLine,
+  parseLines
+}
diff --git a/2021/day-05/vents.test.js b/2021/day-05/vents.test.js
@@ -0,0 +1,74 @@
+/* eslint-env mocha */
+const { expect } = require('chai')
+const { render, chartLine, parseLines } = require('./vents')
+
+const testData = `0,9 -> 5,9
+8,0 -> 0,8
+9,4 -> 3,4
+2,2 -> 2,1
+7,0 -> 7,4
+6,4 -> 2,0
+0,9 -> 2,9
+3,4 -> 1,4
+0,0 -> 8,8
+5,5 -> 8,2`
+
+const sampleMap = `.......1..
+..1....1..
+..1....1..
+.......1..
+.112111211
+..........
+..........
+..........
+..........
+222111....`
+
+const parsedTestData = parseLines(testData)
+
+describe('--- Day 5: Hydrothermal Venture ---', () => {
+  describe('Part 1', () => {
+    describe('render()', () => {
+      it('displays a visual map of the vents', () => {
+        expect(render([[0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
+          [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
+          [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
+          [0, 1, 1, 2, 1, 1, 1, 2, 1, 1],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [2, 2, 2, 1, 1, 1, 0, 0, 0, 0]]))
+          .to.equal(sampleMap)
+      })
+    })
+    describe('chartLine()', () => {
+      it('charts a line between two points', () => {
+        // 10x10 empty grid
+        let data = [...new Array(10)].map(() => {
+          return [...new Array(10)].map(() => 0)
+        })
+        // Map some horizontal and vertical lines
+        data = chartLine(data, 0, 9, 5, 9)
+        data = chartLine(data, 9, 4, 3, 4)
+        data = chartLine(data, 2, 2, 2, 1)
+        data = chartLine(data, 7, 0, 7, 4)
+        data = chartLine(data, 0, 9, 2, 9)
+        data = chartLine(data, 3, 4, 1, 4)
+        expect(render(data)).to.equal(sampleMap)
+      })
+    })
+    it('skips diagonal lines', () => {
+      // 10x10 empty grid
+      let data = [...new Array(10)].map(() => {
+        return [...new Array(10)].map(() => 0)
+      })
+      // Map some lines
+      parsedTestData.forEach((row) => {
+        data = chartLine(data, ...row)
+      })
+      expect(render(data)).to.equal(sampleMap)
+    })
+  })
+})
