Seek the Name, Seek the Fame
The little cat is so famous, that many couples tramp over hill and dale to Byteland, and asked the little cat to give names to their newly-born babies. They seek the name, and at the same time seek the fame. In order to escape from such boring job, the innovative little cat works out an easy but fantastic algorithm:
Step1. Connect the father's name and the mother's name, to a new string S.
Step2. Find a proper prefix-suffix string of S (which is not only the prefix, but also the suffix of S).
Example: Father='ala', Mother='la', we have S = 'ala'+'la' = 'alala'. Potential prefix-suffix strings of S are {'a', 'ala', 'alala'}. Given the string S, could you help the little cat to write a program to calculate the length of possible prefix-suffix strings of S? (He might thank you by giving your baby a name:)
Input
The input contains a number of test cases. Each test case occupies a single line that contains the string S described above.
Restrictions: Only lowercase letters may appear in the input. 1 <= Length of S <= 400000.
Output
For each test case, output a single line with integer numbers in increasing order, denoting the possible length of the new baby's name.
Sample Input
ababcababababcabab
aaaaa
Sample Output
2 4 9 18
1 2 3 4 5
Source
POJ Monthly--2006.01.22,Zeyuan Zhu
题目类型:KMP中Next数组的应用
算法分析:直接将读入字符串的Next数组求出,然后从后向前将不是0的Next[len]的值记录下来,然后对所有的记录排序并输出
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#include <iostream> #include <fstream> #include <sstream> #include <algorithm> #include <iomanip> #include <cstring> #include <cstdio> #include <cmath> #include <map> #include <string> #include <vector> #include <stack> #include <queue> #include <set> #include <list> #include <ctime> using namespace std; const int INF = 0x7FFFFFFF; const int maxn = 400000 + 66; int Next[maxn], len; int output[maxn], out_len; string s; void Build () { Next[0] = -1, Next[1] = 0; int k = 0, i; for (i = 2; i <= len; i++) { while (k >= 0 && s[i-1] != s[k]) k = Next[k]; Next[i] = ++k; } } int main() { // ifstream cin ("aaa.txt"); while (cin >> s) { len = s.length (); out_len = 0; Build (); while (Next[len] != -1) { if (Next[len] != 0) output[out_len++] = Next[len]; len = Next[len]; } sort (output, output + out_len); int i; for (i = 0; i < out_len; i++) cout << output[i] << " "; cout << s.length () << endl; } return 0; } |
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