KMPnext数组循环节理解 HDU1358

Posted 2020-07-12 相儒以沫

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

int next1[1000010];
int m;
char b[1000010];

void build_next()
{
    int i=0;
    int j=-1;
    next1[0]=-1;
    while(i<m)
    {
        while(j!=-1&&b[i]!=b[j])
        {
            j=next1[j];
        }
        next1[++i]=++j;
    }
}

int main()
{
    int num=1;
    while(scanf("%d",&m)!=EOF)
    {
        if(m==0)
            break;
        scanf("%s",&b);
        cout<<"Test case #"<<num<<endl;
        num++;
        build_next();
        for(int i=2;i<=m;i++)
        {
            if(next1[i]==0)
                continue;
            int jie=i-next1[i];
            if(i%jie==0)
            {
               cout<<i<<" "<<(i/jie)<<endl;
            }
        }
        cout<<endl;
    }
    return 0;
}