回溯算法_N皇后

Sub 回溯算法_N皇后()
    n = 8
    ReDim ar(n)
    cnt = nqueen(n, 0, ar, 0)
    Debug.Print (cnt)
End Sub

Public Function nqueen(n, row, res, count)
    If row = n Then count = count + 1: nqueen = count
    For col = 0 To n - 1
        res(row) = col
        If isOk(row, col, res) Then count = nqueen(n, row + 1, res, count)
    Next
    nqueen = count
End Function

Private Function isOk(row, col, res) As Boolean
    For i = 0 To row - 1
        If res(i) = col Then isOk = False: Exit Function
        If row - i = col - res(i) Or row - i = res(i) - col Then isOk = False: Exit Function
    Next
    isOk = True
End Function