Restore IP Addresses

Leetcode 93.

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class Solution {
    public List<String> restoreIpAddresses(String s) {
    List<String> addresses = new ArrayList<>();
    StringBuilder tempAddress = new StringBuilder();
    backtricking(s,addresses,tempAddress,0);
    
    return addresses; 
   }
   private void backtricking(String input,List<String> address,StringBuilder tempAddress,int k){
    //recursion stop condition
     if(k == 4 || input.length() == 0){
        //collect result 
        if(k == 4 && input.length() == 0){
          address.add(tempAddress.toString());  
        }
         return;
     }
     //for loop :  Set of elements in this layer
     for(int i = 0; i < 3 && i < input.length();i++){
         //process nodes according to the requirements
         if(i != 0 && input.charAt(0) == '0'){
             break;
         }
         String part = input.substring(0,i+1);
         if(Integer.valueOf(part) <= 255){
             if(tempAddress.length() != 0){
                 part = "." + part;
             }
             tempAddress.append(part);
             //recursion
             backtricking(input.substring(i+1),address,tempAddress,k+1);
             //backtricking and undo the previous processing node
             tempAddress.delete(tempAddress.length() - part.length(),tempAddress.length());
         }
         
     }

   }
}