Find the contiguous subarray within an array (containing at least one number) which has the largest product.
For example, given the array [2,3,-2,4],
the contiguous subarray [2,3] has the largest product = 6.
这题跟“最大连续子序列和”非常类似，只不过变成了“最大连续子序列积”，所以解决思路也很类似。
仅仅有一个小细节需要注意，就是负负得正，两个负数的乘积是正数，因此我们不仅要跟踪最大值，还要跟踪最小值。
{% codesnippet "./code/maximum-product-subarray."+book.suffix, language=book.suffix %}{% endcodesnippet %}