POJ 2752 同一个串的前后串

题解东北赛回来再补

#include<stdio.h>
#include<string.h>

int next[500000];
int ans[500000];
char str[500000];

void get_next(int m)
{
   int j ,k;
   j = 0 ,k = -1;
   next[0] = -1;
   while(j < m)
   {
       if(k == -1 || str[k] == str[j])
       next[++j] = ++k;
       else k = next[k];
   }
}

int main ()
{
    while(~scanf("%s" ,str))
    {
        int m = strlen(str);
        get_next(m);
        int an = 0;
        ans[++an] = m;
        while(next[ans[an]])
        {
           int tmp = next[ans[an]];
           ans[++an] = tmp;
        }
        for(int i = an ;i >= 1 ;i --)
        if(i == an) printf("%d" ,ans[i]);
        else printf(" %d" ,ans[i]);
        printf("\n");
     }
     return 0;
}