lcs using memoisation

// C++ program to memoize
// recursive implementation of LCS problem
#include <bits/stdc++.h>
using namespace std;

const int maximum = 1000;
int check=0;
int lcs(string X, string Y, int m, int n, int dp[][maximum])
{
    check++;
    if (m == 0 || n == 0)
        return 0;

    if (dp[m - 1][n - 1] != -1)
        return dp[m - 1][n - 1];

    if (X[m - 1] == Y[n - 1]) {

        dp[m - 1][n - 1] = 1 + lcs(X, Y, m - 1, n - 1, dp);

        return dp[m - 1][n - 1];
    }
    else {

        dp[m - 1][n - 1] = max(lcs(X, Y, m, n - 1, dp),
                            lcs(X, Y, m - 1, n, dp));

        return dp[m - 1][n - 1];
    }
}

int main()
{

    string X = "AGGTAB";
    string Y = "GXTXAYB";
    int m = X.length();
    int n = Y.length();

    int dp[m][maximum];

    memset(dp, -1, sizeof(dp));

    cout << "Length of LCS: " << lcs(X, Y, m, n, dp);
    cout<<endl<<check<<endl;

    return 0;
}