Add old 2017 puzzle 3.

2017/3/3.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"math"
+)
+
+// spiralIndex computes the x, y offsets for a counter-clockwise spiral.  It
+// assumes a cartesian coordinate system centered at 0,0 with an index of 1.
+func spiralIndex(addr int) (xoff, yoff int) {
+	r := math.Sqrt(float64(addr))
+	i, f := math.Modf(r)
+	log.Printf("addr = %d r = %f i = %f f = %f", addr, r, i, f)
+	if f == 0 {
+		i := int(i)
+		// Bottom right corner.
+		return (i - 1) / 2, -(i - 1) / 2
+	}
+	return 0, 0
+}
+
+func stepCount(cell int) int {
+	cnt := 0
+	return cnt
+}
+func main() {
+	fmt.Println(stepCount(265149))
+}