longest common substring ,giving error why?

Question

import java.util.Arrays;

public class Solution {
public static int lcs(String str1, String str2){
int dp[][]=new int [str1.length()][str2.length()];
for(int r[]:dp){
Arrays.fill(r, -1);
}
return helper(0,0,str1,str2,0,dp);
}
public static int helper(int i,int j,String s1, String s2,int currentlength,int dp[][]){
if(i>=s1.length()||j>=s2.length()) return currentlength;
if(dp[i][j]!=-1) return dp[i][j];

int pick=0;
if(s1.charAt(i)==s2.charAt(j)) pick= helper(i+1, j+1, s1, s2,currentlength+1,dp);
int notpick=Math.max(helper(i+1, j, s1, s2, 0,dp), helper(i, j+1, s1, s2, 0,dp));

dp[i][j]= Math.max(currentlength, Math.max(pick, notpick));
return currentlength=dp[i][j];

}
}

Answer 1

writing your code in the post makes it difficult for anyone to debug your code/see error(s) it is throwing. Please save your code in the playground and include a link to it in your post.

other things to consider when posting for help:
-what error(s) are you getting?
-what should your code return/display on console?
-what kind of input do you need to provide when running the code?
-is this from a lesson? if so, what lesson? what is the objective?

also, you have two codes in your post, which one are you wanting help with?

Answer 2

I did it Like this :

import java.util.*;

public class Program
{
static boolean isSub(String ss, String[] lst) {
int c=0;
for (String w : lst) if (w.contains(ss)) c += 1;
return c == lst.length;
}

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

//String[] ws = "SoloLearn Learning LearningIsFun Learnable".split(" ");
String[] ws = sc.nextLine().split(" ");
String fw = ws[0];
String lcs = fw.charAt(0) + ""; // String.valueOf();

for (int i=0; i<fw.length(); i++) {
for (int j=i+2; j<fw.length()+1; j++) {
//System.out.format("%d %c %d %s \n", i, fw.charAt(i), j, fw.substring(i, j) );
if (isSub( fw.substring(i, j), ws) )
if ( fw.substring(i, j).length() > lcs.length() ) lcs = fw.substring(i, j);

}
}
System.out.println (lcs);
}