Added the four first days of 2015

Yes i'm gonna do them all !

Signed-off-by: Avior <github@avior.me>

2015/day-3/part-1.ts

@@ -0,0 +1,34 @@
+import fs from 'fs'
+
+const input = fs.readFileSync(__dirname + '/input.txt').toString()
+	.split('') as Array<'<' | '>' | 'v' | '^'>
+
+const poses: Array<`${number}:${number}`> = ['0:0']
+
+let x = 0
+let y = 0
+
+for (const direction of input) {
+	switch (direction) {
+		case '>':
+			x++
+			break;
+		case '<':
+			x--
+			break;
+		case '^':
+			y--
+			break;
+		case 'v':
+			y++
+			break;
+	}
+	const v: `${number}:${number}` = `${x}:${y}`
+	if (!poses.includes(v)) {
+		poses.push(v)
+	}
+}
+
+console.log(
+	"Result:", poses.length
+)

2015/day-3/part-2.ts

@@ -0,0 +1,49 @@
+import fs from 'fs'
+
+const input = fs.readFileSync(__dirname + '/input.txt').toString()
+	.split('') as Array<'<' | '>' | 'v' | '^'>
+
+const poses: Array<`${number}:${number}`> = ['0:0']
+
+let x = 0
+let y = 0
+
+let roboX = 0
+let roboY = 0
+
+for (let i = 0; i < input.length; i++) {
+	const direction = input[i]
+	let xChange = 0
+	let yChange = 0
+	switch (direction) {
+		case '>':
+			xChange++
+			break;
+		case '<':
+			xChange--
+			break;
+		case '^':
+			yChange--
+			break;
+		case 'v':
+			yChange++
+			break;
+	}
+	let v: `${number}:${number}`
+	if (i % 2 === 0) { // santa
+		x += xChange
+		y += yChange
+		v = `${x}:${y}`
+	} else { // roboSanta
+		roboX += xChange
+		roboY += yChange
+		v = `${roboX}:${roboY}`
+	}
+	if (!poses.includes(v)) {
+		poses.push(v)
+	}
+}
+
+console.log(
+	"Result:", poses.length
+)