Solution2.cpp

class Solution {
public:
    long long maximumTotalCost(vector<int>& nums) {
        long long f = LLONG_MIN / 2, g = 0;
        for (int x : nums) {
            long long ff = max(f, g) + x, gg = f - x;
            f = ff;
            g = gg;
        }
        return max(f, g);
    }
};