C++ recursive solution

[user4210]

class Solution {
private:
    int target, size;
    vector<vector<int> > result;
    vector<int> tmp, nums;
    
public:
    vector<vector<int> > fourSum(vector<int>& nums, int target) {
        int depth = 4;
        if (nums.size() >= depth) {
            this->target = target;
            this->nums = nums;
            this->size = this->nums.size();
            std::sort(this->nums.begin(), this->nums.end());
            depth--;
            for (int i = 0; i < this->size - depth; i++) {	
            	if (isTargetExist(i, depth)) {
            	    if (i == 0 || this->nums[i-1] != this->nums[i]) {
                        findTargets(depth, i, 0);
                    }	
	         }
            }    
        }
        return result;
    }
    
private:
	    
   bool isTargetExist(int i, int depth) {
       int sum1 = nums[i];
       int sum2 = sum1;
       for(depth; depth > 0; depth-- ) {
           sum1 += nums[size - depth];
    	   sum2 += nums[++i];
	}
        return sum1 >= target && sum2 <= target;
    }
	
    void findTargets(int depth, int index, int sum) {
        if (depth == 0) {
            sum += nums[index];
            if (sum == target) {
                tmp.push_back(nums[index]);
                result.push_back(tmp);
                tmp.pop_back();   
            }
            return;
        }
	depth--;
        sum += nums[index];
        tmp.push_back(nums[index]);
        for (int i = index + 1; i < this->size - depth; i++) {
            if ((i == index + 1) || (nums[i - 1] != nums[i])) {
                findTargets(depth, i, sum);
            }
        }
        tmp.pop_back();
    }
};