<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:
    void compute(std::vector<std::vector<std::vector<int>>>& vals, std::vector<int>& nums,
        std::vector<char>& ops, int l, int r) {
            std::cout << l << " " << r << std::endl;
            if (!vals[l][r].empty()) {
                return;
            }
            if (l == r) {
                vals[l][r].push_back(nums[l]);
                return;
            }

            for (int o = l; o <= r - 1; ++o) {
                compute(vals, nums, ops, l, o);
                compute(vals, nums, ops, o+1, r);
                if (ops[o] == '+') {
                    for (int lv : vals[l][o]) {
                        for (int rv : vals[o+1][r]) {
                            vals[l][r].push_back(lv + rv);
                        }   
                    }
                } else if (ops[o] == '-') {
                    for (int lv : vals[l][o]) {
                        for (int rv : vals[o+1][r]) {
                            vals[l][r].push_back(lv - rv);
                        }   
                    }
                } else {
                    for (int lv : vals[l][o]) {
                        for (int rv : vals[o+1][r]) {
                            vals[l][r].push_back(lv * rv);
                        }   
                    }
                }
            }
        }

    vector<int> diffWaysToCompute(string expression) {
        istringstream buf{expression};
        std::vector<int> nums;
        std::vector<char> ops;

        int n; buf >> n;
        nums.push_back(n);
        while (buf.peek() != EOF) {
            int n; char c;
            buf >> c >> n;
            nums.push_back(n);
            ops.push_back(c);
        }

        std::cout << nums.size() << std::endl;
        std::cout << ops.size() << std::endl;

        std::vector<std::vector<std::vector<int>>> vals;
        for (int i = 0; i < nums.size(); i++) {
            vals.push_back(std::vector<std::vector<int>>(nums.size()));
        }

        compute(vals, nums, ops, 0, nums.size() - 1);
        return std::vector<int>(vals[0][nums.size() - 1].begin(), vals[0][nums.size() - 1].end());

    }
};
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