Difference between revisions of "2019 ECNU XCPC April Selection 2"
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= 2019 ECNU XCPC April Selection 2 = | = 2019 ECNU XCPC April Selection 2 = | ||
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| + | 开始算法专题场。如果做的很不顺手的，需要阅读相关资料来提高。 | ||
== Problem A == | == Problem A == | ||
Revision as of 05:02, 6 April 2019
2019 ECNU XCPC April Selection 2
开始算法专题场。如果做的很不顺手的，需要阅读相关资料来提高。
Problem A
Problem B
Problem C
涉及算法：KMP。
对于一个字符串的前缀$x$，显然前缀$Next[x]$是最大公共前后缀，$Next[Next[x]]$也是他的公共前后缀。
于是最大的循环节就是最后一个$Next$嵌套中$Next[y]=0$的前缀$y$。
不知道对于每一位都是$Next$嵌套会不会$TLE$。但是可以通过 dp 做到线性的。