<p>Given a string <code>expression</code> of numbers and operators, return <em>all possible results from computing all the different possible ways to group numbers and operators</em>. You may return the answer in <strong>any order</strong>.</p>

<p>The test cases are generated such that the output values fit in a 32-bit integer and the number of different results does not exceed <code>10<sup>4</sup></code>.</p>

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

<pre>
<strong>Input:</strong> expression = &quot;2-1-1&quot;
<strong>Output:</strong> [0,2]
<strong>Explanation:</strong>
((2-1)-1) = 0 
(2-(1-1)) = 2
</pre>

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

<pre>
<strong>Input:</strong> expression = &quot;2*3-4*5&quot;
<strong>Output:</strong> [-34,-14,-10,-10,10]
<strong>Explanation:</strong>
(2*(3-(4*5))) = -34 
((2*3)-(4*5)) = -14 
((2*(3-4))*5) = -10 
(2*((3-4)*5)) = -10 
(((2*3)-4)*5) = 10
</pre>

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

<ul>
	<li><code>1 &lt;= expression.length &lt;= 20</code></li>
	<li><code>expression</code> consists of digits and the operator <code>&#39;+&#39;</code>, <code>&#39;-&#39;</code>, and <code>&#39;*&#39;</code>.</li>
	<li>All the integer values in the input expression are in the range <code>[0, 99]</code>.</li>
</ul>

class Solution {
public:
    vector<int> diffWaysToCompute(string expression) {
        vector<int> result;
        for (int i = 0; i < expression.size(); i++) {
            if (expression[i] == '+' || expression[i] == '-' || expression[i] == '*') {
                string left = expression.substr(0, i);
                string right = expression.substr(i + 1);
                vector<int> leftResults = diffWaysToCompute(left);
                vector<int> rightResults = diffWaysToCompute(right);
                for (int l : leftResults) {
                    for (int r : rightResults) {
                        if (expression[i] == '+') result.push_back(l + r);
                        else if (expression[i] == '-') result.push_back(l - r);
                        else result.push_back(l * r);
                    }
                }
            }
        }
        if (result.empty()) {
            result.push_back(stoi(expression));
        }
        return result;
    }
};
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