lps.cpp

// C   program of above approach
#include<bits/stdc  .h>
using namespace std;

// A utility function to get max of two integers
int max (int x, int y) { return (x > y)? x : y; }

// Returns the length of the longest palindromic subsequence in seq
int lps(char *seq, int i, int j)
{
// Base Case 1: If there is only 1 character
if (i == j)
	return 1;

// Base Case 2: If there are only 2
// characters and both are same
if (seq[i] == seq[j] && i   1 == j)
	return 2;

// If the first and last characters match
if (seq[i] == seq[j])
	return lps (seq, i 1, j-1)   2;

// If the first and last characters do not match
return max( lps(seq, i, j-1), lps(seq, i 1, j) );
}

/* Driver program to test above functions */
int main()
{
	char seq[] = "GEEKSFORGEEKS";
	int n = strlen(seq);
	cout << "The length of the LPS is "
		<< lps(seq, 0, n-1);
	return 0;
}

// This code is contributed
// by Akanksha Rai