June 2018 Update

Task/Solve-a-Holy-Knights-tour/Go/solve-a-holy-knights-tour.go

@@ -0,0 +1,94 @@
+package main
+
+import "fmt"
+
+var moves = [][2]int{
+    {-1, -2}, {1, -2}, {-1, 2}, {1, 2}, {-2, -1}, {-2, 1}, {2, -1}, {2, 1},
+}
+
+var board1 = " xxx    " +
+    " x xx   " +
+    " xxxxxxx" +
+    "xxx  x x" +
+    "x x  xxx" +
+    "sxxxxxx " +
+    "  xx x  " +
+    "   xxx  "
+
+var board2 = ".....s.x....." +
+    ".....x.x....." +
+    "....xxxxx...." +
+    ".....xxx....." +
+    "..x..x.x..x.." +
+    "xxxxx...xxxxx" +
+    "..xx.....xx.." +
+    "xxxxx...xxxxx" +
+    "..x..x.x..x.." +
+    ".....xxx....." +
+    "....xxxxx...." +
+    ".....x.x....." +
+    ".....x.x....."
+
+func solve(pz [][]int, sz, sx, sy, idx, cnt int) bool {
+    if idx > cnt {
+        return true
+    }
+    for i := 0; i < len(moves); i++ {
+        x := sx + moves[i][0]
+        y := sy + moves[i][1]
+        if (x >= 0 && x < sz) && (y >= 0 && y < sz) && pz[x][y] == 0 {
+            pz[x][y] = idx
+            if solve(pz, sz, x, y, idx+1, cnt) {
+                return true
+            }
+            pz[x][y] = 0
+        }
+    }
+    return false
+}
+
+func findSolution(b string, sz int) {
+    pz := make([][]int, sz)
+    for i := 0; i < sz; i++ {
+        pz[i] = make([]int, sz)
+        for j := 0; j < sz; j++ {
+            pz[i][j] = -1
+        }
+    }
+    var x, y, idx, cnt int
+    for j := 0; j < sz; j++ {
+        for i := 0; i < sz; i++ {
+            switch b[idx] {
+            case 'x':
+                pz[i][j] = 0
+                cnt++
+            case 's':
+                pz[i][j] = 1
+                cnt++
+                x, y = i, j
+            }
+            idx++
+        }
+    }
+
+    if solve(pz, sz, x, y, 2, cnt) {
+        for j := 0; j < sz; j++ {
+            for i := 0; i < sz; i++ {
+                if pz[i][j] != -1 {
+                    fmt.Printf("%02d  ", pz[i][j])
+                } else {
+                    fmt.Print("--  ")
+                }
+            }
+            fmt.Println()
+        }
+    } else {
+        fmt.Println("Cannot solve this puzzle!")
+    }
+}
+
+func main() {
+    findSolution(board1, 8)
+    fmt.Println()
+    findSolution(board2, 13)
+}