746. Min Cost Climbing Stairs

/** * @param {number[]} cost * @return {number} */ var minCostClimbingStairs = function(cost) { const length = cost.length; for (let i = 2; i < length; i++) { cost[i] += Math.min(cost[i - 1], cost[i - 2]); } return Math.min(cost[length - 1], cost[length - 2]); }; minCostClimbingStairs([10, 15, 20]); //?