fine, I'll put them on github

3/3.go

@@ -0,0 +1,90 @@
+package main
+
+import "fmt"
+import "math"
+import "time"
+import "os"
+import "strconv"
+
+// go run 3.go <input>
+
+/*
+
+"Debugging is twice as hard as writing the code in the first place.
+ Therefore, if you write the code as cleverly as possible, you are,
+ by definition, not smart enough to debug it." -- Brian W. Kernighan
+
+I probably should have just brute forced this, it took me ages to track
+down the off-by-one error I had for even squares *some* of the time...
+
+*/
+
+func main() {
+
+	start := time.Now()
+
+	target, _ := strconv.Atoi(os.Args[1])
+	squareSize := int(math.Ceil(math.Sqrt(float64(target))))
+	startVal := (squareSize-1)*(squareSize-1) + 1
+
+	dirX := 0
+	dirY := 0
+	min := 0
+	max := 0
+	posX := 0
+	posY := 0
+
+	if (squareSize % 2) == 1 {
+		min = -1 * (squareSize - 1) / 2
+		max = (squareSize - 1) / 2
+		dirX = 0
+		dirY = -1
+		posX = min
+		posY = max
+
+		fmt.Println("odd", squareSize)
+		fmt.Println("start:", startVal, "min:", min, "max:", max)
+
+	} else {
+		min = (-1 * (squareSize) / 2) + 1
+		max = (squareSize) / 2
+		dirX = 0
+		dirY = 1
+		posX = max
+		posY = min
+
+		fmt.Println("even", squareSize)
+		fmt.Println("start:", startVal, "min:", min, "max:", max)
+
+	}
+
+	for i := startVal; i < target; i++ {
+		fmt.Println(i, posX, posY)
+
+		if dirY == -1 && posY == min {
+			dirY = 0
+			dirX = 1
+		}
+		if dirY == 1 && posY == max {
+			dirY = 0
+			dirX = -1
+		}
+		if dirX == -1 && posX == min {
+			dirY = -1
+			dirX = 0
+		}
+		if dirX == 1 && posX == max {
+			dirY = 1
+			dirX = 0
+		}
+
+		posX += dirX
+		posY += dirY
+	}
+
+	fmt.Println("result:", posX, posY, (math.Abs(float64(posX)) + math.Abs(float64(posY))))
+
+	t := time.Now()
+	elapsed := t.Sub(start)
+	fmt.Println(elapsed, "ms")
+}