LCS.cpp

/* A Naive recursive implementation of LCS problem */
#include <bits/stdc++.h>

int max(int a, int b);

/* Returns length of LCS for X[0..m-1], Y[0..n-1] */
int lcs(char* X, char* Y, int m, int n)
{
	if (m == 0 || n == 0)
		return 0;
	if (X[m - 1] == Y[n - 1])
		return 1 + lcs(X, Y, m - 1, n - 1);
	else
		return max(lcs(X, Y, m, n - 1), lcs(X, Y, m - 1, n));
}

/* Utility function to get max of 2 integers */
int max(int a, int b)
{
	return (a > b) ? a : b;
}

/* Driver program to test above function */
int main()
{
	char X[] = "AGGTAB";
	char Y[] = "GXTXAYB";

	int m = strlen(X);
	int n = strlen(Y);

	printf("Length of LCS is %d\n", lcs(X, Y, m, n));

	return 0;
}