LintCode "Maximum Subarray II"

Like "Best Time to Buy Stock III" with "Longest continuous subarray"

class Solution {
public:
    /**
     * @param nums: A list of integers
     * @return: An integer denotes the sum of max two non-overlapping subarrays
     */
    int maxTwoSubArrays(vector<int> nums) {
        int n = nums.size();
        
        vector<int> l(n), r(n);
        //  Left
        l[0] = nums[0];
        int lmax = l[0], sofar = l[0];
        for(int i = 1; i < n; i ++)
        {
            lmax = max(nums[i], lmax + nums[i]);
            sofar = max(lmax, sofar);
            l[i] = sofar;
        }
        
        // Right
        r[n-1] = nums.back();
        int rmax = nums.back(); sofar = nums.back();
        for(int i = n - 2; i >= 0; i --)
        {
            rmax = max(nums[i], rmax + nums[i]);
            sofar = max(rmax, sofar);
            r[i] = sofar;
        }
        
        //  Final
        int ret = INT_MIN;
        for(int i = 0; i < n - 1; i ++)
        {
            ret = max(ret, l[i] + r[i + 1]);
        }
        return ret;
    }
};