摘要：
https://leetcode.com/problems/bitwise-and-of-numbers-range/ 解题思路： 先硬来，超时。 看大神的解法，结论是这道题其实就是要找m和n的bit common prefix。而不需要从m一直算到n。 The hardest part of th 阅读全文
摘要：
https://leetcode.com/problems/rotate-array/ Given an array, rotate the array to the right by k steps, where k is non-negative. Example 1: Example 2: N 阅读全文