<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 {
public:
    vector<int> ans;
    void solve(int ind, string& num, long long x, long long y, vector<int>& sub) {
        if(ind==num.size()) {
            ans.push_back(x);
            ans.push_back(y);
            ans.insert(ans.end(), sub.begin(), sub.end());
            return;
        }
        vector<int> v;
        long long z = x+y;
        for(int i=ind; i<num.size(); i++) {
            string s = num.substr(ind, i-ind+1);
            long long t = stoll(s);
            if(t>z || t>(1LL<<31) || to_string(t)!=s) return;
            if(t==z) {
                sub.push_back(t);
                solve(i+1, num, y, z, sub);
                sub.pop_back();
            }
        }
    }
    vector<int> splitIntoFibonacci(string num) {
        int n = num.size();
        for(int i=0; i<n-2; i++) {
            string a = num.substr(0, i+1);
            long long x = stoll(a);
            if(x>=(1LL<<31) || to_string(x)!=a) break;
            for(int j=i+1; j<n-1; j++) {
                string b = num.substr(i+1, j-i);
                long long y = stoll(b);
                if(y>=(1LL<<31) || to_string(y)!=b) break;
                vector<int> sub;
                solve(j+1, num, x, y, sub);
                if(ans.size()) {
                    ans[0]=x;
                    ans[1]=y;
                    return ans;
                }
            }
        }
        return ans;
    }
};
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