Package g0601_0700.s0679_24_game

Class Solution

java.lang.Object
g0601_0700.s0679_24_game.Solution
public class Solution extends java.lang.Object
679 - 24 Game.

Hard

You are given an integer array cards of length 4. You have four cards, each containing a number in the range [1, 9]. You should arrange the numbers on these cards in a mathematical expression using the operators ['+', '-', '*', '/'] and the parentheses '(' and ')' to get the value 24.

You are restricted with the following rules:

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

Return true if you can get such expression that evaluates to 24, and false otherwise.

Example 1:

Input: cards = [4,1,8,7]

Output: true

Explanation: (8-4) * (7-1) = 24

Example 2:

Input: cards = [1,2,1,2]

Output: false

Constraints:

  • cards.length == 4
  • 1 <= cards[i] <= 9

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    judgePoint24(int[] nums)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • judgePoint24

      public boolean judgePoint24(int[] nums)