Introduction

In this blog post, we will explore how to solve the LeetCode problem "746" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given an integer array cost where cost[i] is the cost of ith step on a staircase. Once you pay the cost, you can either climb one or two steps. You can either start from the step with index 0, or the step with index 1. Return the minimum cost to reach the top of the floor. Example 1: Input: cost = [10,15,20] Output: 15 Explanation: You will start at index 1. - Pay 15 and climb two steps to reach the top. The total cost is 15. Example 2: Input: cost = [1,100,1,1,1,100,1,1,100,1] Output: 6 Explanation: You will start at index 0. - Pay 1 and climb two steps to reach index 2. - Pay 1 and climb two steps to reach index 4. - Pay 1 and climb two steps to reach index 6. - Pay 1 and climb one step to reach index 7. - Pay 1 and climb two steps to reach index 9. - Pay 1 and climb one step to reach the top. The total cost is 6. Constraints: 2 <= cost.length <= 1000 0 <= cost[i] <= 999

Explanation

Here's the breakdown of the solution:

• Dynamic Programming: The core idea is to use dynamic programming to store the minimum cost to reach each step. We build up the solution from the bottom up.
• Base Cases: The minimum cost to reach step 0 is cost[0], and the minimum cost to reach step 1 is cost[1].

• Recurrence Relation: For each subsequent step i, the minimum cost to reach it is the minimum of (cost to reach i-1 + cost[i]) and (cost to reach i-2 + cost[i]). We only need to keep track of the last two costs.

• Runtime Complexity: O(n) & Storage Complexity: O(1)

Code

    def minCostClimbingStairs(cost):
    """
    Calculates the minimum cost to reach the top of the staircase.

    Args:
        cost: A list of integers representing the cost of each step.

    Returns:
        The minimum cost to reach the top of the staircase.
    """
    n = len(cost)
    if n <= 1:
        return 0  # Or handle appropriately based on problem definition

    down_one = cost[1]
    down_two = cost[0]

    for i in range(2, n):
        temp = down_one
        down_one = min(down_one, down_two) + cost[i]
        down_two = temp

    return min(down_one, down_two)