#8 Daily Problems -AddTwoHugeNumbers

Hi guys today is my 8th day of solving the one problem per day.

Problem:

You’re given 2 huge integers represented by linked lists. Each linked list element is a number from 0 to 9999 that represents a number with exactly 4 digits. The represented number might have leading zeros. Your task is to add up these huge integers and return the result in the same format.

Example

• For a = [9876, 5432, 1999] and b = [1, 8001], the output should be
  addTwoHugeNumbers(a, b) = [9876, 5434, 0].
• Explanation: 987654321999 + 18001 = 987654340000.
• For a = [123, 4, 5] and b = [100, 100, 100], the output should be
  addTwoHugeNumbers(a, b) = [223, 104, 105].
• Explanation: 12300040005 + 10001000100 = 22301040105.

Input/Output

• [execution time limit] 3 seconds (java)
• [input] linkedlist.integer a
• The first number, without its leading zeros.
• Guaranteed constraints:
  0 ≤ a size ≤ 104,
  0 ≤ element value ≤ 9999.
• [input] linkedlist.integer b
• The second number, without its leading zeros.
• Guaranteed constraints:
  0 ≤ b size ≤ 104,
  0 ≤ element value ≤ 9999.
• [output] linkedlist.integer
• The result of adding a and b together, returned without leading zeros in the same format.

My solution:

// Singly-linked lists are already defined with this interface:
// class ListNode<T> {
//   ListNode(T x) {
//     value = x;
//   }
//   T value;
//   ListNode<T> next;
// }
//
ListNode<Integer> addTwoHugeNumbers(ListNode<Integer> a, ListNode<Integer> b) {
int i=0;
BigInteger total=null;
String firstNumber="", secondNumber="";
while(a!=null){
if(i==0){
firstNumber=""+a.value;
}else{
firstNumber=firstNumber+""+String.format("%04d" , a.value);
}
a=a.next;
i++;
}
i=0;
while(b!=null){
if(i==0){
secondNumber=""+b.value;
}else{
secondNumber=secondNumber+""+String.format("%04d" , b.value);
}
b=b.next;
i++;
}
i=0;
total= new BigInteger(""+firstNumber).add(new BigInteger(""+secondNumber));
ListNode<Integer> listNode= new ListNode(0);
ListNode temp=null;
while (total.signum() >0) {
System.out.println(total.remainder(new BigInteger(""+10000)) );
int remaindervalue = total.remainder(new BigInteger(""+10000)).intValue();
if(i==0){
listNode=new ListNode(remaindervalue);
temp=listNode;
}else{
temp.next=new ListNode(remaindervalue);
temp=temp.next;
}
total = total.divide(new BigInteger(""+10000));
i++;
}
ListNode<Integer> prev=null,current = listNode, next;
while(current!=null)
{
next=current.next;
current.next=prev;
prev=current;
current=next;
}
listNode = prev;
return listNode;
}

Please learn and let me learn something from you guys. Please give me some claps if you like otherwise leave some suggestion to improve myslef. Thanks and bye…

Happy coding!

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