在硬币兑换类型的问题中将递归函数重构为迭代函数

def coin_change_recursive(coins, amount):
    if amount == 0:
        return 0
    if amount < 0:
        return float('inf')
    
    min_coins = float('inf')
    for coin in coins:
        result = coin_change_recursive(coins, amount - coin)
        if result != float('inf'):
            min_coins = min(min_coins, 1 + result)
    
    return min_coins

def coin_change_iterative(coins, amount):
    # 初始化一个数组，dp[i] 表示兑换金额 i 所需的最少硬币数量
    dp = [float('inf')] * (amount + 1)
    dp[0] = 0  # 兑换金额 0 所需的硬币数量为 0
    
    for i in range(1, amount + 1):
        for coin in coins:
            if i - coin >= 0:
                dp[i] = min(dp[i], dp[i - coin] + 1)
    
    return dp[amount] if dp[amount] != float('inf') else -1