Code:
#include iostream
#include cstring
using namespace std;
void preKMP(string pattern, int f[])
{
int m = pattern.length(), k;
f[0] = -1;
for (int i = 1; i < m; i++)
{
k = f[i - 1];
while (k >= 0)
{
if (pattern[k] == pattern[i - 1])
break;
else
k = f[k];
}
f[i] = k + 1;
}
}
//check whether target string contains pattern
bool KMP(string pattern, string target)
{
int m = pattern.length();
int n = target.length();
int f[m];
preKMP(pattern, f);
int i = 0;
int k = 0;
while (i < n)
{
if (k == -1)
{
i++;
k = 0;
}
else if (target[i] == pattern[k])
{
i++;
k++;
if (k == m)
return 1;
}
else
k = f[k];
}
return 0;
}
int main()
{
string tar = "san and linux training";
string pat = "lin";
if (KMP(pat, tar))
cout<<"'"<
else
cout<<"'"<
pat = "sanfoundry";
if (KMP(pat, tar))
cout<<"'"<
else
cout<<"'"<
return 0;
}
Output:
'lin' found in string 'san and linux training'
'sanfoundry' not found in string 'san and linux training'
------------------
(program exited with code: 1)
Press return to continue
More C++ Programs:
