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Given N rational numbers in the form "numerator/denominator", you are supposed to calculate their sum. Input Specification: Each input file contains o 阅读全文
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The task is simple: given any positive integer N, you are supposed to count the total number of 1's in the decimal form of the integers from 1 to N. F 阅读全文
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The highest building in our city has only one elevator. A request list is made up with N positive numbers. The numbers denote at which floors the elev 阅读全文
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Given a sequence of positive numbers, a segment is defined to be a consecutive subsequence. For example, given the sequence {0.1, 0.2, 0.3, 0.4}, we h 阅读全文
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“答案正确”是自动判题系统给出的最令人欢喜的回复。本题属于PAT的“答案正确”大派送 —— 只要读入的字符串满足下列条件，系统就输出“答案正确”，否则输出“答案错误”。 得到“答案正确”的条件是： 1. 字符串中必须仅有P, A, T这三种字符，不可以包含其它字符；2. 任意形如 xPATx 的字符 阅读全文
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二分查找 1、查找某元素。循环条件 low <= high，最终结果位mid， 如果查询失败则返回-1。 2、查找第一个满足条件的元素。 1）被排好序的待搜索序列一定是从左到右先不满足条件，然后满足条件； 2）传入的high = N时，在搜索不到满足条件的数时，会返回N（假想N位置有数字）； 若不想 阅读全文
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For any 4-digit integer except the ones with all the digits being the same, if we sort the digits in non-increasing order first, and then in non-decre 阅读全文
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There is a classical process named partition in the famous quick sort algorithm. In this process we typically choose one element as the pivot. Then th 阅读全文
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The string APPAPT contains two PAT's as substrings. The first one is formed by the 2nd, the 4th, and the 6th characters, and the second one is formed 阅读全文
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Given an increasing sequence S of N integers, the median is the number at the middle position. For example, the median of S1={11, 12, 13, 14} is 12, a 阅读全文