题意：一摞书，无序，可以把某本书抽到最顶上，问最少抽几次可以使书有序。 继续阅读【思维/模拟】Reorder the Books
Given an array with n integers, and you are given two indices i and j (i ≠ j) in the array. You have to find two integers in the range whose difference is minimum. You have to print this value. The array is indexed from 0 to n-1.
继续阅读【区间查询】Crawling in process