#include <bits/stdc++.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
(i < N) {
if
(pat[j] == txt[i]) {
j++;
i++;
}
if
(j == M) {
printf
(
"Found pattern at index %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;
}
}
}
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[] =
"ABABDABACDABABCABAB"
;
char
pat[] =
"ABABCABAB"
;
KMPSearch(pat, txt);
return
0;
}