KMP-Algo.c

#include <stdio.h>
#include <string.h>
void computeLPSArray(char *pat, int M, int *lps);
void KMPSearch(char *pat, char *txt)
{
    int M = strlen(pat);
    int N = strlen(txt);
    int lps[M];
    computeLPSArray(pat, M, lps);
    int i = 0;
    int j = 0;
    while ((N - i) >= (M - j))
    {
        if (pat[j] == txt[i])
        {
            j++;
            i++;
        }
        if (j == M)
        {
            printf("%d ", i - j);
            j = lps[j - 1];
        }
        else if (i < N && pat[j] != txt[i])
        {
            if (j != 0)
                j = lps[j - 1];
            else
                i = i + 1;
        }
    }
    printf("\n");
    for (int i = 0; i < M; i++)
        printf("%d ", lps[i]);
}
void computeLPSArray(char *pat, int M, int *lps)
{
    int len = 0;
    lps[0] = 0;
    int i = 1;
    while (i < M)
    {
        if (pat[i] == pat[len])
        {
            len++;
            lps[i] = len;
            i++;
        }
        else
        {
            if (len != 0)
                len = lps[len - 1];
            else
            {
                lps[i] = 0;
                i++;
            }
        }
    }
}
int main()
{
    char txt[50];
    char pat[50];
    scanf("%[^\n]s", txt);
    scanf("%s", pat);
    KMPSearch(pat, txt);
    return 0;
}