luogu3375 【模板】KMP字符串匹配

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int lena, lenb, nxt[1000005];
char a[1000005], b[1000005];
void mknxt(){
    int j=0, k;
    k = nxt[0] = -1;
    while(j<lenb){
        if(k==-1 || b[j]==b[k]) nxt[++j] = ++k;
        else    k = nxt[k];
    }
}
void kmp(){
    int i=0, j=0;
    while(i<lena){
        if(j==-1 || a[i]==b[j]) i++, j++;
        else    j = nxt[j];
        if(j==lenb) printf("%d\n", i-j+1), j = nxt[j];
    }
}
int main(){
    scanf("%s %s", a, b);
    lena = strlen(a);
    lenb = strlen(b);
    mknxt();
    kmp();
    for(int i=1; i<=lenb; i++)  printf("%d ", nxt[i]);
    return 0;
}