二分法的模版需要牢牢记:二分法是利用的decrease and conquer is different with divide and conquer
在有序的数组中寻找一个跟target value有关的index或value
比如:
总之 sorted数组与target related to index (value)
because it is supper big array so it isn't possible to search in that array,we need think to decrease it "binary search " and then where is the "end"
the end can use the “倍增法Exponential Backoff”