<p>You are given a string of digits <code>num</code>, such as <code>&quot;123456579&quot;</code>. We can split it into a Fibonacci-like sequence <code>[123, 456, 579]</code>.</p>

<p>Formally, a <strong>Fibonacci-like</strong> sequence is a list <code>f</code> of non-negative integers such that:</p>

<ul>
	<li><code>0 &lt;= f[i] &lt; 2<sup>31</sup></code>, (that is, each integer fits in a <strong>32-bit</strong> signed integer type),</li>
	<li><code>f.length &gt;= 3</code>, and</li>
	<li><code>f[i] + f[i + 1] == f[i + 2]</code> for all <code>0 &lt;= i &lt; f.length - 2</code>.</li>
</ul>

<p>Note that when splitting the string into pieces, each piece must not have extra leading zeroes, except if the piece is the number <code>0</code> itself.</p>

<p>Return any Fibonacci-like sequence split from <code>num</code>, or return <code>[]</code> if it cannot be done.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> num = &quot;1101111&quot;
<strong>Output:</strong> [11,0,11,11]
<strong>Explanation:</strong> The output [110, 1, 111] would also be accepted.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> num = &quot;112358130&quot;
<strong>Output:</strong> []
<strong>Explanation:</strong> The task is impossible.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> num = &quot;0123&quot;
<strong>Output:</strong> []
<strong>Explanation:</strong> Leading zeroes are not allowed, so &quot;01&quot;, &quot;2&quot;, &quot;3&quot; is not valid.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= num.length &lt;= 200</code></li>
	<li><code>num</code> contains only digits.</li>
</ul>

class Solution
{
    vector<long> splitIntoFibonacciHelp(string num, int ind, long last2ndDigit, long lastDigit)
    {
        for (int i = ind; i < num.length(); i++)
        {
            if(num[ind] == '0' && i > ind)
            {
                break;
            }

            if (last2ndDigit == -1)
            {
                string substring = num.substr(ind, i - ind + 1);
                // cout<<"1: "<<substring<<endl;
                long dig = stol(substring);

                if(dig > INT_MAX)
                {
                    return {};
                }

                vector<long> ans = splitIntoFibonacciHelp(num, i + 1, lastDigit, dig);

                if (ans.size() > 0) // got an ans
                {
                    ans.insert(ans.begin(), dig);
                    return ans;
                }
            }
            else
            {
                string substring = num.substr(ind, i - ind + 1);
                // cout<<"2: "<<substring<<endl;
                long dig = stol(substring);

                if(dig > INT_MAX)
                {
                    return {};
                }

                if (last2ndDigit + lastDigit == dig)
                {
                    if (i == num.length() - 1)
                    {
                        return {dig};
                    }
                    else
                    {
                        vector<long> ans = splitIntoFibonacciHelp(num, i + 1, lastDigit, dig);

                        if (ans.size() > 0) // got an ans
                        {
                            ans.insert(ans.begin(), dig);
                            return ans;
                        }
                    }
                }
            }
        }

        return {};
    }

public:
    vector<int> splitIntoFibonacci(string num)
    {
        vector<long> ans = splitIntoFibonacciHelp(num, 0, -1, -1);

        vector<int> ansInt;
        for(int i=0;i<ans.size();i++)
        {
            ansInt.push_back(ans[i]);
        }

        return ansInt;
    }
};
12200