字符串练习题：【CF119D】 String Transformation(KMP或哈希，枚举，各种优化)

Let s be a string whose length equals n. Its characters are numbered from 0 to n - 1,i and j are integers,0 ≤ i < j < n. Let's define functionf as follows:

f(s, i, j) = s[i + 1...j - 1] + r(s[j... n - 1]) + r(s[0...i]).

Here s[p... q] is a substring of strings, that starts in position p and ends in position q (inclusive); "+" is the string concatenation operator;r(x) is a string resulting from writing the characters of thex string in the reverse order. If j = i + 1, then the substring s[i + 1...j - 1] is considered empty.

You are given two strings a and b. Find such values of i andj, that f(a, i, j) = b. Numberi should be maximally possible. If for thisi there exists several valid values of j, choose the minimal j.