error in this code?

Question

package DP1;

public class CoinSumprob {

public static void main(String[] args) {
// TODO Auto-generated method stub
int coins[] = { 1, 2, 3 };
int n = coins.length;
int dp[][]=new int [n+1][4+1];
for(int i=0;i<dp.length;i++) {
for(int j=0;j<dp.length;j++) {
dp[i][j]=-1;
}
}
System.out.println(count(coins, n, 4,dp));
}
static int count(int coins[], int n, int sum,int dp[][])
{

// If sum is 0 then there is 1 solution
// (do not include any coin)
if (sum == 0)
return 1;

// If sum is less than 0 then no
// solution exists
if (sum < 0)
return 0;

// If there are no coins and sum
// is greater than 0, then no
// solution exist
if (n <= 0)
return 0;

// count is sum of solutions (i)
// including coins[n-1] (ii) excluding coins[n-1]
// return count(coins, n - 1, sum)
// + count(coins, n, sum - coins[n - 1]);
int small1,small2;
if(dp[n-1][sum]==-1) {
small1=count(coins, n-1, sum, dp);
dp[n-1][sum]=small1;
}
else {
small1=dp[n-1][sum];
}
if(dp[n-1][sum-coins[n-1]]==-1) {
small2=count(coins, n-1, sum-coins[n-1], dp);
dp[n-1][sum-coins[n-1]]=small2;
}
else {
small2=dp[n-1][sum-n-1];
}

return small1+small2;

}

}

Answer 1

Abdi Jawate don't attach of someone else code in Q&A discussion forum

Answer 2

https://code.sololearn.com/cJg6RQo4eV4r/?ref=app
https://code.sololearn.com/W34f4i49oXhk/?ref=app
https://code.sololearn.com/WgS5h04rlqIC/?ref=app