Day 5 solution

.gitignore

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+output

js/day5.js

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+const { readFromFile, printSolution } = require('./utility')
+const flags = require('flags')
+const assert = require('assert')
+
+let coordinates = {}
+
+const solve = (sample) => {
+    const inputs = readFromFile(5, sample)
+    for (line of inputs.split("\n")) {
+        let value = line.split(" -> ")
+        findPassedCoordinate(value[0], value[1])
+    }
+
+    printSolution(countOverlap())
+
+    coordinates = {}
+    for (line of inputs.split("\n")) {
+        let value = line.split(" -> ")
+        findPassedCoordinate(value[0], value[1], true)
+    }
+    printSolution(countOverlap())
+}
+
+const findPassedCoordinate = (start, end, secondPart = false) => {
+    start = start.split(',').map(Number)
+    end = end.split(',').map(Number)
+
+    if (start[0] !== end[0] && start[1] !== end[1] && !secondPart) {
+        return
+    } else if (start[0] !== end[0] && start[1] !== end[1] && secondPart) {
+        assert.equal(Math.abs(start[0] - end[0]) === Math.abs(start[1] - end[1]), true)
+
+        while (start[0] !== end[0] && start[1] !== end[1]) {
+            checkAndAddCoordinate(`${start[0]},${start[1]}`)
+            if (start[0] > end[0]) {
+                start[0]--
+            }else{
+                start[0]++
+            }
+
+            if (start[1] > end[1]) {
+                start[1]--
+            }else{
+                start[1]++
+            }
+        }
+        checkAndAddCoordinate(`${start[0]},${start[1]}`)
+    } else if (start[0] !== end[0]) {
+        let a = Math.min(start[0], end[0])
+        let b = Math.max(start[0], end[0])
+        for (let i = a; i <= b; i++) {
+            checkAndAddCoordinate(`${i},${start[1]}`)
+        }
+    } else if (start[1] !== end[1]) {
+        let a = Math.min(start[1], end[1])
+        let b = Math.max(start[1], end[1])
+        for (let i = a; i <= b; i++) {
+            checkAndAddCoordinate(`${start[0]},${i}`)
+        }
+    }
+}
+
+const countOverlap = () => {
+    // count overlap
+    let overlap = 0
+    for (v of Object.values(coordinates)) {
+        if (v > 1) {
+            overlap++
+        }
+    }
+
+    return overlap
+}
+
+const checkAndAddCoordinate = (str) => {
+    if (!coordinates[str]) {
+        coordinates[str] = 1
+    } else {
+        coordinates[str]++
+    }
+}
+
+flags.defineBoolean("sample", false, "run with sample")
+flags.parse()
+
+solve(flags.get("sample"))