摘要：
We have an array A of non-negative integers. For every (contiguous) subarray B = [A[i], A[i+1], ..., A[j]] (with i <= j), we take the bitwise OR of al 阅读全文
摘要：
Given two integers A and B, return any string S such that: S has length A + B and contains exactly A 'a' letters, and exactly B 'b' letters; The subst 阅读全文