标签:des style blog http io ar for strong sp
Period
Time Limit: 3000MS |
|
Memory Limit: 30000K |
Total Submissions: 13511 |
|
Accepted: 6368 |
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 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
Source
Southeastern Europe 2004
和poj1961相同,http://blog.csdn.net/winddreams/article/details/40268107
不过是多加了一个对从头到每个字符的判断。
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int next[1100000] ;
char s[1100000] ;
void getnext(int l)
{
int j = 0 , k = -1 ;
next[0] = -1 ;
while( j < l )
{
if( k == -1 || s[j] == s[k] )
next[++j] = ++k ;
else
k = next[k] ;
}
}
int main()
{
int n , i , num = 1 , l ;
while(scanf("%d", &n) && n)
{
scanf("%s", s);
getnext(n);
printf("Test case #%d\n", num++);
for(i = 1 ; i <= n ; i++)
{
l = i - next[i] ;
if( i%l==0 && i/l != 1 )
printf("%d %d\n", i, i/l);
}
printf("\n");
}
return 0;
}
poj1961--Period(KMP求最小循环节)
标签:des style blog http io ar for strong sp
原文地址:http://blog.csdn.net/winddreams/article/details/40268155