An ascending array of distinct integers nums has been rotated at some unknown pivot (so [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2] ). Given nums and a target , return the index of target , or -1 if it is not present. Your algorithm must run in O(log n) time. Input format Input is [nums, target] , e.g. [[4,5,6,7,0,1,2],0] .