kmp algorithm
#include<bits/stdc++.h>
using namespace std;
void createlps(int lps[],string pattern,int n)
{
int i=0;
int j=1;
lps[0]=0;
while(j<n)
{
if(pattern[i]==pattern[j])
{
lps[j]=i+1;
i++;
j++;
}
else
{
if(i!=0)
{
i=lps[i-1];
}
else
{
lps[j]=0;
j++;
}
}
}
}
void kmp(string str,string pattern,int n,int lps[])
{
int i=0;
int j=0;
int size_of_str=str.size();
while(i<size_of_str)
{
if(pattern[j]==str[i])
{
i++;
j++;
}
if(j==n)
{
cout<<"Found at:"<<i-j;
j=lps[j-1];
}
else if(i<size_of_str&&pattern[j]!=str[i])
{
if(j!=0)
{
j=lps[j-1];
}
else
{
i++;
}
}
}
}
int main()
{
string str;
cin>>str;
string pattern;
cin>>pattern;
int n=pattern.size();
int lps[n];
createlps(lps,pattern,n);
for(int i=0;i<n;i++)
{
cout<<lps[i]<<" ";
}
kmp(str,pattern,n,lps);
return 0;
}