Create day03.kt

advent-of-code-2017/src/cpateritsas/day03.kt

@@ -0,0 +1,83 @@
+package kotlin.math
+
+fun part1(v:Int) {
+    var start = 1
+    var step = 0
+    var m = start
+    var length = 0
+
+    while (v > m) {
+        length = length + 8
+        m = m + length
+        step++
+    }
+
+    var diff = m - v
+    var side = length / 4
+    var d = if (side>0) (diff % side) - side/2 else 0
+
+    var distance = step + abs(d)
+
+    println("step:$step m:$m length:$length")
+    println("diff:$diff side:$side d:$d")
+
+    println("distance:$distance")
+}
+
+class Spiral {
+    val firstDigit = 1
+    val neighboorsDiff = listOf(Pair(1,1),Pair(1,0),Pair(1,-1),Pair(0,1),Pair(0,-1),Pair(-1,-1),Pair(-1,0),Pair(-1,1))
+
+    var mem = linkedMapOf(Pair(0,0) to firstDigit)
+
+    fun findNeighboors(p:Pair<Int,Int>):List<Pair<Int,Int>> {
+       	return neighboorsDiff.map{n -> Pair(n.first + p.first, n.second + p.second) }
+    }
+
+    fun fillValue(pair:Pair<Int,Int>):Int {
+        val vv = findNeighboors(pair)
+                    .mapNotNull{p->mem.get(p)}
+        			.sum()
+
+        mem.put(pair,vv)        
+        return vv
+    }
+
+    fun fillUpTo(limit: Int) {
+        var radious = 0
+        var currentValue = 0
+
+        while (currentValue <= limit) {
+            radious++
+            var x = radious
+            var y = 1 - radious
+            while (y < radious && currentValue <= limit) {
+                currentValue = fillValue(Pair(x,y))                
+                y++
+            }
+            while (x > -radious && currentValue <= limit) {
+                currentValue = fillValue(Pair(x,y))                
+                x--
+            }
+            while (y > -radious && currentValue <= limit) {
+                currentValue = fillValue(Pair(x,y))                
+                y--
+            }
+            while (x < radious && currentValue <= limit) {
+                currentValue = fillValue(Pair(x,y))                
+                x++
+            }
+            if(currentValue > limit) break
+            currentValue = fillValue(Pair(x,y))
+        }        
+    }
+}
+
+fun main(args: Array<String>) {
+    var v = 347991
+    part1(v)
+    var s = Spiral() 
+    s.fillUpTo(v) //349975
+    println(s.mem)
+
+}