Here, We see 24 Game LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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24 Game LeetCode Solution

Problem Statement

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

24 Game LeetCode Solution C++

class Solution {
public:
vector<double>fill(double a,double b){
  vector<double>v={a+b,a-b,b-a,a*b};
    if(a!=0) v.push_back(b/a);
    if(b!=0) v.push_back(a/b);
  return v;
}
bool check(vector<double>&newl){
  if(newl.size()==1){  
return abs(newl[0]-24)<=0.1;
  }
  for(int i=0;i<newl.size();i++){
    for(int j=i+1;j<newl.size();j++){
            vector<double> newList;
                for (int k = 0; k < newl.size(); k++) {
                    if (k != j && k != i) {
                        newList.push_back(newl[k]);
                    }
                }
   vector<double>res;
     res=fill(newl[i],newl[j]);
           for(int l=0;l<res.size();l++){
             newList.push_back(res[l]);
             if(check(newList)) return true;
               newList.pop_back();
         }
  }}
  return false;
}
    bool judgePoint24(vector<int>& cards) {
        vector<double> newl(cards.begin(), cards.end());
        return check(newl);
    }
};Code language: PHP (php)

24 Game LeetCode Solution Java

class Solution {
    public boolean judgePoint24(int[] cards) {
        List<Double> in=new ArrayList<>();
        for(int i : cards){
            in.add((double)i);
        }
        return dfs(in);
    }
    
    public boolean dfs(List<Double> cards){
        if(cards.size()==1){
            if(Math.abs(cards.get(0)-24.0)<0.001) return true;
            return false;
        }
        for(int i=0;i<cards.size();i++){
            for(int j=i+1;j<cards.size();j++){
                List<Double> possibleCombinations=generatePossibleResults(cards.get(i),cards.get(j));
                for(double c:possibleCombinations){
                    List<Double> next=new ArrayList<>();
                    next.add(c);
                    for(int k=0;k<cards.size();k++){
                        if(k!=i && k!=j) next.add(cards.get(k));
                    }                    
                    if(dfs(next)) return true;
                } 
            }
        }
        return false;
    }

    private List<Double> generatePossibleResults(double a, double b) {
        List<Double> res = new ArrayList<>();
        res.add(a + b);
        res.add(a - b);
        res.add(b - a);
        res.add(a * b);
        res.add(a / b);
        res.add(b / a);
        return res;
    }
}Code language: PHP (php)

24 Game LeetCode Solution JavaScript

var judgePoint24 = function(cards) {
    if (cards.length == 1) {
        return Math.abs(cards[0] - 24) < 0.01;
    }

    let ans = false;
    for (let i = 0; i < cards.length; ++i) {
        for (let j = 0; j < i; ++j) {
            const rest = [];
            for (let k = 0; k < cards.length; ++k) {
                if (k != i && k != j) {
                    rest.push(cards[k]);
                }
            }
            const target = [
                cards[i] + cards[j], cards[i] - cards[j],
                cards[j] - cards[i], cards[i] * cards[j]
            ];
            if (cards[i]) target.push(cards[j] / cards[i]);
            if (cards[j]) target.push(cards[i] / cards[j]);
            for (const t of target) {
                ans = ans || judgePoint24([t, ...rest]);
                if (ans) return true;
            }
        }
    }
    return ans;
};Code language: JavaScript (javascript)

24 Game Solution Python

class Solution:
    def judgePoint24(self, cards):
        if not cards:
            return False
        return self.dfs(cards, 4)

    def dfs(self, cards, n):
        if n == 1:
            if abs(cards[0] - 24) <= 1E-6 :
                return True
        for i in range(0, n):
            for j in range(i + 1, n):
                a, b = cards[i], cards[j]
                cards[j] = cards[n - 1]
                for temp in [a + b, a - b, b - a, a * b]:
                    cards[i] = temp
                    if self.dfs(cards, n - 1):
                        return True
                if a != 0:
                    cards[i] = b / a
                    if self.dfs(cards, n - 1):
                        return True
                if b != 0:
                    cards[i] = a / b
                    if self.dfs(cards, n - 1):
                        return True
                cards[i], cards[j] = a, b 
        return FalseCode language: HTML, XML (xml)