小G的ACM之路

Perfect Hash  Perfect Software, Inc. has obtained a government contract to examine text flowing through a high-speed network for the occurrence of certain words. Your boss, Wally Perfect,

Problem C: Babelfish You have just moved from Waterloo to a big city. The people here speak an incomprehensible dialect of a foreign language. Fortunately, you have a dictionary to help you underst

Problem A Concatenation of Languages Input File: Standard Input Output: Standard Output   A language is a set of strings. And the concatenation of two languages is the set of all strings that are

Problem C - Sumsets Given S, a set of integers, find the largest d such that a + b + c = d where a, b, c, and d are distinct elements of S. Input Several S, each consisting of a line containing an

The Spot Game  The game of Spot is played on an NxN board as shown below for N = 4. During the game, alternate players may either place a black counter (spot) in an empty square or remove

Problem C Happy Number Time Limit 1 Second   Let the sum of the square of the digits of a positive integer S0 be represented by S1. In a similar way, let the sum of the sq

Problem E: Compound Words You are to find all the two-word compound words in a dictionary. A two-word compound word is a word in the dictionary that is the concatenation of exactly two other words

题意： 给定一个序列a[0],a[1]….a[n-1]和一个整数k，问是否有这样的两个下标使得 NP-Sum(i,j)=k，这里 NP-Sum(i,j)=a[i]-a[i+1]+a[i+2]-…+(-1)^(j-1)*a[j]。 解析： 首先题目提示说要用快速输入，如果不用快速输入可能会超时。 现在来讨论一下这题的做法： 我们可以维护这个序列的后缀和，然后枚举sum[i]查看

题意： 给一个数组，记数组中出现次数最多的元素出现的次数为这个数组的美丽值，求这个数组长度最短的子数组（要连续），使得该子数组的美丽值与原数组美丽值相等。要求输出子数组的起始和结束位置下标（从1开始）。 解析： 也是个水题。每个数最大才10610^6，用hash存储每个数出现的次数即可。输入的时候用一个结构体记录最左边的位置，和最右边的位置，以及区间的长度和每个值出现的次数，再把hash存入