K ordered LCS dynamic problem

#1

why it gives tle in second test case???

import java.util.*;
public class Main {

public static void main(String args[]) {    

  Scanner kb=new Scanner(System.in);
   int n=kb.nextInt();
   int m=kb.nextInt();
   int k=kb.nextInt();

   int []arr=new int[n];
   int []arr1=new int[m];
   long [][][]dp=new long[2005][2005][8];  

    for(int i=0;i<n;i++)
	 arr[i]=kb.nextInt();
   
    for(int i=0;i<m;i++)
	 arr1[i]=kb.nextInt();

 long a=korderedLCS(arr,arr1,0,0,k,dp);
 System.out.println(a);	
}

public static long korderedLCS(int[] a, int[] b, int i, int j, int k, long[][][] dp) {
if (a.length == i || b.length == j) {
return 0;
}
if (dp[i][j][k] != 0) {
return dp[i][j][k];
}
long res = 0;
if (a[i] == b[j]) {
res = 1 + korderedLCS(a, b, i + 1, j + 1, k, dp);
} else {
if (k > 0) {
res = 1 + korderedLCS(a, b, i + 1, j + 1, k - 1, dp);
}
res = Math.max(res, korderedLCS(a, b, i + 1, j, k, dp));
res = Math.max(res, korderedLCS(a, b, i, j + 1, k, dp));
}
dp[i][j][k] = res;
return res;

}

}

#2

@abhishekg
you didn’t intialize the DP properly with -1
as zero can be the possible ans then it must return from there.

import java.util.*;
public class Main {

public static void main(String args[]) {

Scanner kb=new Scanner(System.in);
int n=kb.nextInt();
int m=kb.nextInt();
int k=kb.nextInt();

int []arr=new int[n];
int []arr1=new int[m];
long [][][]dp=new long[n+1][m+1][k+1];
for(int i=0;i<=n;i++) {
for(int j=0;j<=m;j++) {
for(int z=0;z<=k;z++) {
dp[i][j][z] = -1;
}
}
}

for(int i=0;i<n;i++)
 arr[i]=kb.nextInt();

for(int i=0;i<m;i++)
 arr1[i]=kb.nextInt();

long a=korderedLCS(arr,arr1,0,0,k,dp);
System.out.println(a);
}
public static long korderedLCS(int[] a, int[] b, int i, int j, int k, long[][][] dp) {
if (a.length == i || b.length == j) {
return 0;
}
if (dp[i][j][k] != -1) {
return dp[i][j][k];
}
long res = 0;
if (a[i] == b[j]) {
res = 1 + korderedLCS(a, b, i + 1, j + 1, k, dp);
} else {
if (k > 0) {
res = 1 + korderedLCS(a, b, i + 1, j + 1, k - 1, dp);
}

res = Math.max(res, korderedLCS(a, b, i + 1, j, k, dp));
res = Math.max(res, korderedLCS(a, b, i, j + 1, k, dp));
}
dp[i][j][k] = res;
return res;

}
}

here is the correct code.

#3

I hope I’ve cleared your doubt. I ask you to please rate your experience here
Your feedback is very important. It helps us improve our platform and hence provide you
the learning experience you deserve.

On the off chance, you still have some questions or not find the answers satisfactory, you may reopen
the doubt.