1143. Longest Common Subsequence

class Solution {
public:
    string s1,s2;
int n,m;
int dp[1006][1006];
int lcs(int i,int j)
{
     if(i==n or j==m)return 0;

      if(dp[i][j]!=-1)return dp[i][j];

      int ret;
      if(s1[i]==s2[j])
      {
          ret=1+lcs(i+1,j+1);
      }else{

        ret=max(lcs(i+1,j),lcs(i,j+1));

      }


      dp[i][j]=ret;

      return dp[i][j];


}
    int longestCommonSubsequence(string text1, string text2) {

         s1=text1;
         s2=text2;
         n=s1.size();
         m=s2.size();
         memset(dp,-1,sizeof(dp));
         return lcs(0,0);

    }

};