Given an array consisting of n integers, find the contiguous subarray of given length k that has the maximum average value. And you need to output the maximum average value. Input: [1,12,-5,-6,50,3], ...

Input: [-2,0,-1] Output: 0 Explanation: The result cannot be 2, because [-2,-1] is not a subarray. 这个求最大子数组乘积问题是由最大子数组之和 Maximum Subarray 演变而来，但是却比求最大子数组之和要复杂，因为在求和的时候，遇到0，不会改变最大值，遇到负数，也只是会减小最大 ...