题目:http://hzwer.com/3419.html 题意:给你一个全是0的数列,有m种操作[Li,Ri],每次操作就将下标处于[Li,Ri]的元素取反.你可以选若干个操作来使这个数列最后变成别的样子,求最后的数列有多少种 分析: 容易知道如果每个操作都是不能被其他操作的组合替代,那么这个操作就对操作集合有贡献,不妨设有x个这样的操作,既然ans=操作集合的子集数,那么ans=2^x 那么问题的关键就是如何判断一个操作能否被其他操作取代 一个很巧的想法是对于每个操作[Li,Ri],将点Li…

How Many Answers Are Wrong Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 6336    Accepted Submission(s): 2391 Problem Description TT and FF are ... friends. Uh... very very good friends -_____…

Find them, Catch them Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 42416   Accepted: 13045 Description The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang Drago…

传送门 Find them, Catch them Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 42463   Accepted: 13065 Description The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang D…

How Many Answers Are Wrong Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 6349    Accepted Submission(s): 2395 Problem Description TT and FF are ... friends. Uh... very very good friends -_____…

Find them, Catch them Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 43132   Accepted: 13257 Description The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang Drago…

Navigation Nightmare Time Limit: 2000MS   Memory Limit: 30000K Total Submissions: 5939   Accepted: 2102 Case Time Limit: 1000MS Description Farmer John's pastoral neighborhood has N farms (2 <= N <= 40,000), usually numbered/labeled 1..N. A series o…

CF456E Codeforces Round #260 (Div. 1) C Codeforces Round #260 (Div. 2) E http://codeforces.com/contest/455/problem/C C. Civilization time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Andrew p…

Is It A Tree? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 16702    Accepted Submission(s): 3761 Problem Description A tree is a well-known data structure that is either empty (null, void, n…

Navigation Nightmare   Description Farmer John's pastoral neighborhood has N farms (2 <= N <= 40,000), usually numbered/labeled 1..N. A series of M (1 <= M < 40,000) vertical and horizontal roads each of varying lengths (1 <= length <= 1…