比较两个数组，要求从数组最后一个元素开始逐个元素向前比较，如果2个数组长度不等，则只比较较短长度数组个数元素。返回比较中发现的不相等元素的个数。-Compare two arrays, the last element from an array requires start-by-element comparison forward, if the two arrays of unequal length, only the relatively short length of the num