ds_practise/GenerateValidIP.java at main · pavan642/ds_practise · GitHub

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import java.util.LinkedList;
import java.util.Queue;

public class GenerateValidIP {
    //Given a numeric string, generate all possible valid IP addresses by inserting dots.
    // For example, given "25511156", possible valid outputs include:
    //2.55.111.56
    //255.11.1.56
    //255.1.1.156
    private static void generateValidIPAddress(String str){
        // ip address ranges  0 to 256
        // generate sub strings of size 1 to 3 and store in anothe list
        Queue<RequestObject> queue = new LinkedList<>();

        int length = str.length();
        RequestObject requestObject = new RequestObject();
        requestObject.str1 = str.substring(0,1);
        requestObject.str2 = str.substring(1, length);
        requestObject.response = "";
        requestObject.resIpLen = 0;
        requestObject.inputLength = length;
        queue.add(requestObject);

        RequestObject requestObject1 = new RequestObject();
        requestObject1.str1 = str.substring(0,2);
        requestObject1.str2 = str.substring(2, length);
        requestObject1.response = "";
        requestObject1.resIpLen = 0;
        requestObject1.inputLength = length;
        queue.add(requestObject1);

        RequestObject requestObject2 = new RequestObject();
        requestObject2.str1 = str.substring(0,3);
        requestObject2.str2 = str.substring(3, length);
        requestObject2.response = "";
        requestObject2.resIpLen = 0;
        requestObject2.inputLength = length;
        queue.add(requestObject2);
        findIpAddress(queue);
    }

    private static void findIpAddress (Queue<RequestObject> queue){
        while (!queue.isEmpty()){
            RequestObject requestObject = queue.poll();
            int len = requestObject.str2.length();
            if(Integer.parseInt(requestObject.str1) < 256 && requestObject.resIpLen < 4){
                if(requestObject.response.isEmpty()){
                    requestObject.response  =  requestObject.str1;
                } else {
                    requestObject.response  = requestObject.response + "."  + requestObject.str1;
                }
                requestObject.resIpLen = requestObject.resIpLen + 1;
            }
            processAndPrint(requestObject, requestObject.inputLength);

            if(len >= 1){
                RequestObject requestObject1 = new RequestObject();
                requestObject1.str1 = requestObject.str2.substring(0,1);
                requestObject1.str2 = requestObject.str2.substring(1, len);
                requestObject1.response = requestObject.response;
                requestObject1.resIpLen = requestObject.resIpLen;
                requestObject1.inputLength = requestObject.inputLength;
                queue.add(requestObject1);
            }
            if(len >= 2) {
                RequestObject requestObject2 = new RequestObject();
                requestObject2.str1 = requestObject.str2.substring(0,2);
                requestObject2.str2 = requestObject.str2.substring(2, len);
                requestObject2.response = requestObject.response;
                requestObject2.resIpLen = requestObject.resIpLen;
                requestObject2.inputLength = requestObject.inputLength;
                queue.add(requestObject2);
            }
            if(len >= 3){
                RequestObject requestObject3 = new RequestObject();
                requestObject3.str1 = requestObject.str2.substring(0,3);
                requestObject3.str2 = requestObject.str2.substring(3, len);
                requestObject3.response = requestObject.response;
                requestObject3.resIpLen = requestObject.resIpLen;
                requestObject3.inputLength = requestObject.inputLength;
                queue.add(requestObject3);
            }
        }
    }

    static class RequestObject{
        String str1;
        String str2;
        String response = "";
        Integer resIpLen = 0;
        int inputLength;
    }

    private static void processAndPrint(RequestObject requestObject, int inputLength) {
        if(requestObject.response.length() == inputLength + 3){
            System.out.println(requestObject.response);
        }
    }

    public static void main(String[] args) {
        String input = "25511156";
        generateValidIPAddress(input);
    }

}