Period
Time Limit: 2000/1000 MS
(Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 209 Accepted Submission(s): 92
Problem Description
For each prefix of a given string S with N characters
(each character has an ASCII code between 97 and 126, inclusive), we want to
know whether the prefix is a periodic string. That is, for each i (2 <= i
<= N) we want to know the largest K > 1 (if there is one) such that the
prefix of S with length i can be written as AK
, that is A
concatenated K times, for some string A. Of course, we also want to know the
period K.
Input
The input file consists of several test cases. Each test
case consists of two lines. The first one contains N (2 <= N <= 1 000
000) – the size of the string S. The second line contains the string S. The
input file ends with a line, having the number zero on it.
Output
For each test case, output “Test case #” and the
consecutive test case number on a single line; then, for each prefix with
length i that has a period K > 1, output the prefix size i and the period K
separated by a single space; the prefix sizes must be in increasing order.
Print a blank line after each test case.
Sample Input
3
aaa
12
aabaabaabaab
0
Sample Output
Test case #1
2 2
3 3
Test case #2
2 2
6 2
9 3
12 4
求字符串中存在周期的子串的最大循环次数
,KMP
算法的应用之一
.
代码如下
: