Initial data commit

Task/Prime-triangle/Go/prime-triangle.go

@@ -0,0 +1,71 @@
+package main
+
+import "fmt"
+
+var canFollow [][]bool
+var arrang []int
+var bFirst = true
+
+var pmap = make(map[int]bool)
+
+func init() {
+    for _, i := range []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37} {
+        pmap[i] = true
+    }
+}
+
+func ptrs(res, n, done int) int {
+    ad := arrang[done-1]
+    if n-done <= 1 {
+        if canFollow[ad-1][n-1] {
+            if bFirst {
+                for _, e := range arrang {
+                    fmt.Printf("%2d ", e)
+                }
+                fmt.Println()
+                bFirst = false
+            }
+            res++
+        }
+    } else {
+        done++
+        for i := done - 1; i <= n-2; i += 2 {
+            ai := arrang[i]
+            if canFollow[ad-1][ai-1] {
+                arrang[i], arrang[done-1] = arrang[done-1], arrang[i]
+                res = ptrs(res, n, done)
+                arrang[i], arrang[done-1] = arrang[done-1], arrang[i]
+            }
+        }
+    }
+    return res
+}
+
+func primeTriangle(n int) int {
+    canFollow = make([][]bool, n)
+    for i := 0; i < n; i++ {
+        canFollow[i] = make([]bool, n)
+        for j := 0; j < n; j++ {
+            _, ok := pmap[i+j+2]
+            canFollow[i][j] = ok
+        }
+    }
+    bFirst = true
+    arrang = make([]int, n)
+    for i := 0; i < n; i++ {
+        arrang[i] = i + 1
+    }
+    return ptrs(0, n, 1)
+}
+
+func main() {
+    counts := make([]int, 19)
+    for i := 2; i <= 20; i++ {
+        counts[i-2] = primeTriangle(i)
+    }
+    fmt.Println()
+    for i := 0; i < 19; i++ {
+        fmt.Printf("%d ", counts[i])
+    }
+    fmt.Println()
+}