746.Min Cost Climbing Stairs

1-DP

class Solution {
    public int minCostClimbingStairs(int[] cost) {
        int f1 = 0;
        int f2 = 0;
        for(int i = cost.length - 1; i >= 0; i--){
            int f0 = cost[i] + Math.min(f1, f2);
            f2 = f1;
            f1 = f0;
        }
        return Math.min(f1, f2);
    }
}