数据结构实验之串二：字符串匹配

Problem Description

Input

Output

Example Input

abc
a
123456
45
abc
ddd

Example Output

YES
YES
NO

Code realization

#include <stdio.h>
#include <string.h>
int next[1000001];
void Get_next(char str2[])
{
    int i = 0,j = -1;
    int len = strlen(str2);
    next[i] = j;
    while(i<len)
    {
        if(j==-1||str2[i]==str2[j])
        {
            i++;
            j++;
            next[i] = j;
        }
        else
            j = next[j];
    }
}
void KMP(char str1[],char str2[])
{
    Get_next(str2);
    int i = 0, j = 0;
    int len1 = strlen(str1), len2 = strlen(str2);
    while(i<len1&&j<len2)
    {
        if(j==-1||str1[i]==str2[j])
        {
            i++;
            j++;
        }
        else
            j = next[j];
    }
    if(j>=len2)
        printf("YES\n");
    else
        printf("NO\n");
}
int main()
{
    char str1[1000001], str2[1000001];
    while(scanf("%s%s",str1,str2)!=EOF)
    {

        KMP(str1,str2);
    }
    return 0;
}