679. 24 Game

You have 4 cards each containing a number from 1 to 9. You need to judge whether they could operated through *, /, +, -, (, ) to get the value of 24.

Example 1:

Input: [4, 1, 8, 7]
Output: True
Explanation: (8-4) * (7-1) = 24

Example 2:

Input: [1, 2, 1, 2]
Output: False

Note:

1. The division operator / represents real division, not integer division. For example, 4 / (1 - 2/3) = 12.
2. Every operation done is between two numbers. In particular, we cannot use - as a unary operator. For example, with [1, 1, 1, 1] as input, the expression -1 - 1 - 1 - 1 is not allowed.
3. You cannot concatenate numbers together. For example, if the input is [1, 2, 1, 2], we cannot write this as 12 + 12.

# @lc code=start
using LeetCode

function judgePoint24(nums::Vector)::Bool
    n = length(nums)
    if n == 1
        return nums[1] == 24
    else
        for i in 1:n
            for j in 1:n
                if j != i
                    rest = [nums[k] for k in 1:n if k != i && k != j]
                    if judgePoint24([rest..., nums[i] + nums[j]]) ||
                       judgePoint24([rest..., nums[i] - nums[j]]) ||
                       judgePoint24([rest..., nums[j] - nums[i]]) ||
                       judgePoint24([rest..., nums[i] * nums[j]]) ||
                       (!iszero(nums[j]) && judgePoint24([rest..., nums[i]//nums[j]])) ||
                       (!iszero(nums[i]) && judgePoint24([rest..., nums[j]//nums[i]]))
                        return true
                    end
                end
            end
        end
        false
    end
end
# @lc code=end

judgePoint24 (generic function with 1 method)

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