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feat: add solutions to lc problem: No.0679 (doocs#2046)
No.0679.24 Game
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‎solution/0600-0699/0679.24 Game/README.md

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<!-- 这里可写通用的实现逻辑 -->
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**方法一：DFS**
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我们设计一个函数 $dfs(nums)$，其中 $nums$ 表示当前的数字序列，函数返回一个布尔值，表示是否存在一种排列方式，使得这个数字序列可以得到 $24$。
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如果 $nums$ 的长度为 $1$，那么只有当这个数字等于 $24$ 时，我们才返回 $true$，否则返回 $false$。
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否则，我们可以枚举 $nums$ 中的任意两个数 $a$ 和 $b$ 作为左右两个操作数，枚举 $a$ 和 $b$ 之间的运算符 $op$，那么 $a\ op\ b$ 的结果就可以作为新的数字序列的一个元素，我们将其加入到新的数字序列中，并从 $nums$ 中移除 $a$ 和 $b$，然后递归地调用 $dfs$ 函数，如果返回 $true$，那么我们就找到了一种排列方式，使得这个数字序列可以得到 $24$，我们就返回 $true$。
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如果枚举完所有的情况都没有返回 $true$，那么我们就返回 $false$。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def judgePoint24(self, cards: List[int]) -> bool:
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def dfs(nums: List[float]):
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n = len(nums)
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if n == 1:
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if abs(nums[0] - 24) < 1e-6:
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return True
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return False
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ok = False
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for i in range(n):
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for j in range(n):
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if i != j:
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nxt = [nums[k] for k in range(n) if k != i and k != j]
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for op in ops:
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match op:
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case "/":
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if nums[j] == 0:
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continue
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ok |= dfs(nxt + [nums[i] / nums[j]])
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case "*":
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ok |= dfs(nxt + [nums[i] * nums[j]])
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case "+":
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ok |= dfs(nxt + [nums[i] + nums[j]])
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case "-":
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ok |= dfs(nxt + [nums[i] - nums[j]])
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if ok:
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return True
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return ok
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ops = ("+", "-", "*", "/")
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nums = [float(x) for x in cards]
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return dfs(nums)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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private final char[] ops = {'+', '-', '*', '/'};
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public boolean judgePoint24(int[] cards) {
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List<Double> nums = new ArrayList<>();
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for (int num : cards) {
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nums.add((double) num);
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}
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return dfs(nums);
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}
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private boolean dfs(List<Double> nums) {
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int n = nums.size();
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if (n == 1) {
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return Math.abs(nums.get(0) - 24) < 1e-6;
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}
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boolean ok = false;
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for (int i = 0; i < n; ++i) {
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for (int j = 0; j < n; ++j) {
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if (i != j) {
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List<Double> nxt = new ArrayList<>();
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for (int k = 0; k < n; ++k) {
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if (k != i && k != j) {
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nxt.add(nums.get(k));
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}
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}
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for (char op : ops) {
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switch (op) {
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case '/' -> {
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if (nums.get(j) == 0) {
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continue;
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}
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nxt.add(nums.get(i) / nums.get(j));
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}
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case '*' -> {
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nxt.add(nums.get(i) * nums.get(j));
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}
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case '+' -> {
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nxt.add(nums.get(i) + nums.get(j));
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}
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case '-' -> {
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nxt.add(nums.get(i) - nums.get(j));
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}
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}
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ok |= dfs(nxt);
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if (ok) {
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return true;
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}
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nxt.remove(nxt.size() - 1);
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}
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}
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}
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}
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return ok;
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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bool judgePoint24(vector<int>& cards) {
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vector<double> nums;
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for (int num : cards) {
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nums.push_back(static_cast<double>(num));
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}
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return dfs(nums);
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}
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private:
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const char ops[4] = {'+', '-', '*', '/'};
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bool dfs(vector<double>& nums) {
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int n = nums.size();
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if (n == 1) {
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return abs(nums[0] - 24) < 1e-6;
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}
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bool ok = false;
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for (int i = 0; i < n; ++i) {
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for (int j = 0; j < n; ++j) {
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if (i != j) {
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vector<double> nxt;
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for (int k = 0; k < n; ++k) {
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if (k != i && k != j) {
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nxt.push_back(nums[k]);
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}
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}
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for (char op : ops) {
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switch (op) {
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case '/':
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if (nums[j] == 0) {
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continue;
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}
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nxt.push_back(nums[i] / nums[j]);
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break;
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case '*':
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nxt.push_back(nums[i] * nums[j]);
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break;
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case '+':
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nxt.push_back(nums[i] + nums[j]);
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break;
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case '-':
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nxt.push_back(nums[i] - nums[j]);
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break;
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}
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ok |= dfs(nxt);
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if (ok) {
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return true;
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}
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nxt.pop_back();
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}
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}
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}
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}
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return ok;
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}
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};
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```
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### **Go**
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```go
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func judgePoint24(cards []int) bool {
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ops := [4]rune{'+', '-', '*', '/'}
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nums := make([]float64, len(cards))
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for i, num := range cards {
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nums[i] = float64(num)
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}
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var dfs func([]float64) bool
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dfs = func(nums []float64) bool {
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n := len(nums)
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if n == 1 {
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return math.Abs(nums[0]-24) < 1e-6
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}
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ok := false
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for i := 0; i < n; i++ {
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for j := 0; j < n; j++ {
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if i != j {
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var nxt []float64
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for k := 0; k < n; k++ {
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if k != i && k != j {
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nxt = append(nxt, nums[k])
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}
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}
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for _, op := range ops {
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switch op {
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case '/':
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if nums[j] == 0 {
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continue
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}
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nxt = append(nxt, nums[i]/nums[j])
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case '*':
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nxt = append(nxt, nums[i]*nums[j])
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case '+':
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nxt = append(nxt, nums[i]+nums[j])
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case '-':
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nxt = append(nxt, nums[i]-nums[j])
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}
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ok = ok || dfs(nxt)
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if ok {
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return true
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}
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nxt = nxt[:len(nxt)-1]
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}
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}
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}
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}
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return ok
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}
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return dfs(nums)
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}
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```
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### **TypeScript**
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```ts
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function judgePoint24(cards: number[]): boolean {
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const ops: string[] = ['+', '-', '*', '/'];
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const dfs = (nums: number[]): boolean => {
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const n: number = nums.length;
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if (n === 1) {
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return Math.abs(nums[0] - 24) < 1e-6;
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}
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let ok: boolean = false;
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for (let i = 0; i < n; i++) {
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for (let j = 0; j < n; j++) {
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if (i !== j) {
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const nxt: number[] = [];
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for (let k = 0; k < n; k++) {
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if (k !== i && k !== j) {
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nxt.push(nums[k]);
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}
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}
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for (const op of ops) {
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switch (op) {
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case '/':
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if (nums[j] === 0) {
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continue;
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}
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nxt.push(nums[i] / nums[j]);
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break;
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case '*':
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nxt.push(nums[i] * nums[j]);
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break;
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case '+':
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nxt.push(nums[i] + nums[j]);
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break;
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case '-':
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nxt.push(nums[i] - nums[j]);
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break;
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}
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ok = ok || dfs(nxt);
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if (ok) {
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return true;
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}
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nxt.pop();
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}
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}
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}
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}
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return ok;
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};
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return dfs(cards);
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}
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```
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### **...**

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