class Solution {
public:
    int minCostClimbingStairs(vector<int>& cost)
    {
        int lastStep = 0;
        int lastLastStep = 0;
        for (auto i : cost)
        {
            int newLastStep = lastLastStep + i;
            int newLastLastStep = lastStep < newLastStep ? lastStep : newLastStep;
            lastStep = newLastStep;
            lastLastStep = newLastLastStep;
        }
        return std::min(lastStep, lastLastStep);
    }
};