using System;
using System.Collections.Generic;


class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
     *
     * 
     * @param cost int整型一维数组 
     * @return int整型
     */
    public int minCostClimbingStairs (List<int> cost) {
        int[] maxCost = new int[]{0,0,0};
        int k = 0;
        for(int i = 2; i < cost.Count + 1; i++){
            k = i % 3;
            maxCost[k] = Math.Min(maxCost[(k+1)%3] + cost[i-2], maxCost[(k+2)%3] + cost[i-1]);
        }
        return maxCost[k];
    }
}