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 prices int整型一维数组

@return int整型

class Solution
def maxProfit(prices)
# write code here
return 0 if prices.length < 2
return 0 if prices.length == 2 && prices[0] > prices[1]
min = prices[0]
# 差价
rst = 0
(1...prices.length).each{|i|
rst = prices[i] - min if prices[i] - min > rst
min = prices[i] if prices[i] < min
}
rst
end
end