2708. Maximum Strength of a Group

You are given a 0-indexed integer array nums representing the score of students in an exam. The teacher would like to form one non-empty group of students with maximal strength, where the strength of a group of students of indices i<sub>0</sub>, i<sub>1</sub>, i<sub>2</sub>, ... , i<sub>k</sub> is defined as nums[i<sub>0</sub>] * nums[i<sub>1</sub>] * nums[i<sub>2</sub>] * ... * nums[i<sub>k</sub>​].

Input : nums = [3,-1,-5,2,5,-9]

long long maxStrength(vector<int>& nums) 
    {
        int n=nums.size();
        if(n==1)
        {
            return nums[0];
        }

        vector<int> pos;
        vector<int> neg;

        for(int i=0;i<n;i++)
        {
            if(nums[i]<0)
            {
                neg.push_back(nums[i]);
            }
            else
            if(nums[i]>0)
            {
                pos.push_back(nums[i]);
            }
        }

        sort(pos.begin(),pos.end());
        sort(neg.begin(),neg.end());

        long long ans1=0;

        for(int i=0;i<neg.size();i++)
        {
            if(i==0)
            {
                ans1=neg[i];
            }
            else
            {
                if(neg.size()%2==0)
                {
                    ans1=ans1*neg[i];
                }
                else
                {
                    if(i<neg.size()-1)
                    {
                        ans1=ans1*neg[i];
                    }
                }
            }
        }

        long long ans2=0;

        for(int i=0;i<pos.size();i++)
        {
            if(i==0)
            {
                ans2=pos[i];
            }
            else
            {
                ans2=ans2*pos[i];
            }
        }

        if(ans1>0 && ans2>0)
        return ans1*ans2;
        else if(ans1>0)
            return ans1;
        else if(ans2>0)
            return ans2;
        else
            return 0;
    }