POJ 2752 Seek the Name, Seek the Fame(next数组的理解)

做此题，只要理解好next数组就行.......................

 

#include <cstdio>
#include <cmath>
#include <iostream>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;
char str[411111],tmp[411111];
int next[411111],ans[411111];

void getnext(char *t) {
    int i=0,j=-1;
    int len = strlen(t);
    next[0] = -1;
    while(i < len) {
        if(t[i] == t[j] || j == -1) {
            i ++;
            j ++;
            next[i] = j;
        } else j = next[j];
    }
}
/*
int kmp(char *s,char *t) {
    int lens = strlen(s);
    int lena = strlen(t);
    int i=0,j=0;
    while(i < lens && j < lena) {
        if(s[i] == t[j] || j == -1) {
            i++;
            j++;
        } else j = next[j];
    }
    if(j < lena) return -1;
    return i - lena;
}
*/
int main() {
    while(scanf("%s",str) != EOF) {
        strcpy(tmp,str);
        int len = strlen(str);
        int cnt = 0;
        getnext(str);
        int j = next[len];
        ans[cnt++] = j;
        while(j > 1) {
            ans[cnt++] = next[j];
            j = next[j];
        }
        for(int i=cnt-1; i>=0; i--) {
            if(ans[i] != 0)
                printf("%d ",ans[i]);
        }
        printf("%d\n",len);
    }
    return 0;
}