poj2752-Seek the Name, Seek the Fame

//要充分了解next数组所代表的含义

#include<iostream>#include<cstring>#include<cstdio>#include<cmath>#include<algorithm>#include<cstlib>#include<map>#include<queue>#include <deque>#include <list>#include <ctime>#include <stack>#include <vector>#include<set>#define Maxn 400100typedef long long ll;#define FOR(i,j,n) for(int i=j;i<=n;i++)#define DFR(i,j,k) for(int i=j;i>=k;--i)#define lowbit(a) a&-a#define Max(a,b) a>b?a:b#define Min(a,b) a>b?b:aconst int inf = 0x3f3f3f3f;const double pi = acos(-1.0);using namespace std;int next[Maxn],len1,book[Maxn];char p[Maxn];void getNext(){   next[0] = -1;    int i = 0;    int j = -1;    while (i < len1)    {   if (j == -1 || p[i] == p[j]) next[++i] = ++j;        else   j = next[j];    }}int main(){   while(~scanf("%s",p))    {   len1=strlen(p);        getNext();        int cnt=0;        for(int i=len1;next[i]!=-1;i=next[i])        book[cnt++]=i;    <span style="white-space:pre"></span>DFR(i,cnt-1,0)        printf("%d%c",book[i],i==0?'\n':' ');    }    return 0;}