2016 ACM-ICPC NEERC F. Foreign Postcards 题意:有一串由C.W组成的字符串,每次截取长度为k(1<=k<=n且k随机)的前缀,如果该前缀首位为W,则该前缀取反(即C->W,W->C),放到桌上,否则直接放到桌上:重复前面步骤直至字符串被截为空.求最后桌上W的个数期望. 思路:定义dp[i]:以s[i]为首的后缀的W个数期望 则dp[i]=Σ{ (dp[k]+"s[i]到s[k-1]的W或C的个数")/(n-i) }(i+1…

摘要 本文主要列举并求解了2016 ACM/ICPC亚洲区青岛站现场赛的部分真题,着重介绍了各个题目的解题思路,结合详细的AC代码,意在熟悉青岛赛区的出题策略,以备战2018青岛站现场赛. HDU 5984 Pocky 题意 给出一根棒子(可以吃的)的长度x和切割过程中不能小于的长度d,每次随机的选取一个位置切开,吃掉左边的一半,对右边的棒子同样操作,直至剩余的长度不大于d时停止.现在给出x和d,问切割次数的数学期望是多少. 解题思路 当看到第二个样例2 1时,结果是1.693147,联想到ln…

2016 ACM ICPC Asia Region - Tehran A - Tax 题目描述:算税. solution 模拟. B - Key Maker 题目描述:给出\(n\)个序列,给定一个序列,问\(n\)个序列中有多少个序列满足对应位的值小于或等于给定序列的值. solution 模拟. C - IOI 2017 Logo 题目描述:有\(m\)件作品,\(n\)个人投票,每个人可以选三件作品,分别给\(1, 2, 3\)分,每件作品按总分排序,总分相同按得\(3\)分的数量排序,还…

Football Games Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 439    Accepted Submission(s): 157 Problem Description A mysterious country will hold a football world championships---Abnormal Cup…

Friends and Enemies Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 291    Accepted Submission(s): 160 Problem Description On an isolated island, lived some dwarves. A king (not a dwarf) ruled t…

Barricade Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 997    Accepted Submission(s): 306 Problem Description The empire is under attack again. The general of empire is planning to defend his…

Function Time Limit: 7000/3500 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 976    Accepted Submission(s): 375 Problem Description The shorter, the simpler. With this problem, you should be convinced of this tru…

Football Games Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 802    Accepted Submission(s): 309 Problem Description A mysterious country will hold a football world championships---Abnormal Cup…

2016 ACM/ICPC Asia Regional Qingdao Online(部分题解) 5878---I Count Two Three http://acm.hdu.edu.cn/showproblem.php?pid=5878 Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1287    Accepted Submissi…

Different Circle Permutation Time Limit: 3000/1500 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 208    Accepted Submission(s): 101 Problem Description You may not know this but it's a fact that Xinghai Square is…