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The Minimum Length

Time Limit: 1000 MS Memory Limit: 131072 KB 64bit IO Format:
%lld & %llu

Submit Status

Description

There is a string A. The length of A is less than 1,000,000. I rewrite it
again and again. Then I got a new string: AAAAAA…… Now I cut it from two
different position and get a new string B. Then, give you the string B, can
you tell me the length of the shortest possible string A. For example,
A=”abcdefg”. I got abcd efgabcdefgabcde fgabcdefg…. Then I cut the
red part: efgabcdefgabcde as string B. From B, you should find out the
shortest A.

Input

Multiply Test Cases. For each line there is a string B which contains only
lowercase and uppercase charactors. The length of B is no more than 1,000,000.

Output

For each line, output an integer, as described above.

Sample Input

bcabcab
efgabcdefgabcde

Sample Output

3
7

同样还是循环节的考察，求最短循环节。

#include<stdio.h>
#include<iostream>
#include<math.h>
#include<stdlib.h>
#include<ctype.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<queue>
#include<stack>
#include<set>
#include<map>

using namespace std;

char  b[1000500];
int Next[1000500];

void get_next(char b[], int m)
{
    int i = 0,j = -1;
    memset(Next,0,sizeof(Next));
    Next[0] = -1;
    while (b[i])
    {
        if (j == -1 || b[i] == b[j])
        {
            ++i;
            ++j;
            Next[i] = j;
        }
        else
            j = Next[j];
    }
}

int main()
{
    int cases = 1, n, m, i, j;

    while (scanf("%s",&b)!=EOF)
    {
        n = strlen(b);
        get_next(b, n);
        int ans = 0;

        for (int i = 1; b[i-1]; i++)
        {
            int t = Next[i];
            int s = i - t;
            if (i % s == 0 )
            {
                ans = max(ans,s);
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}