[인터뷰비트, InterviewBit] [JAVA] Valid Ip Addresses

Valid Ip Addresses - InterviewBit

코딩테스트 연습 - Valid Ip Addresses

설명

Given a string containing only digits, restore it by returning all possible valid IP address combinations.

A valid IP address must be in the form of A.B.C.D, where A,B,C and D are numbers from 0-255. The numbers cannot be 0 prefixed unless they are 0.

Example:

Given “25525511135”,

return [“255.255.11.135”, “255.255.111.35”]. (Make sure the returned strings are sorted in order)

제한사항

• Make sure the returned strings are sorted in order

 

 

소스코드

public class Solution {
    public boolean isIP(String ip) {
		if (ip.startsWith("0")) {
			if (ip.length() > 1) {
				return false;
			} else {
				return (ip.length() <= 3 && Integer.parseInt(ip) <= 255);
			}
		} else {
			return (ip.length() <= 3 && Integer.parseInt(ip) <= 255);
		}
	}

	public ArrayList<String> restoreIpAddresses(String A) {
		ArrayList<String> answer = new ArrayList<>();

		for (int i = 1; i < A.length(); i++) {
			StringBuilder sb = new StringBuilder(A);
			sb.insert(i, ".");
			String[] splited = sb.toString().split("\\.");
			if (!isIP(splited[0]) || splited[1].length() > 9) continue;
			else {
				for (int j = 1; j < splited[1].length(); j++) {
					StringBuilder sb2 = new StringBuilder(splited[1]);
					sb2.insert(j, ".");
					String[] splited2 = sb2.toString().split("\\.");
					if (!isIP(splited2[0]) || splited2[1].length() > 6) continue;
					else {
						for (int k = 1; k < splited2[1].length(); k++) {
							StringBuilder sb3 = new StringBuilder(splited2[1]);
							sb3.insert(k, ".");
							String[] splited3 = sb3.toString().split("\\.");
							if (!isIP(splited3[0]) || !isIP(splited3[1])) continue;
							else {
//								System.out.println(Integer.parseInt(splited[0]) + "." + Integer.parseInt(splited2[0])
//										+ "." + Integer.parseInt(splited3[0]) + "." + Integer.parseInt(splited3[1]));
								answer.add(Integer.parseInt(splited[0]) + "." + Integer.parseInt(splited2[0])
										+ "." + Integer.parseInt(splited3[0]) + "." + Integer.parseInt(splited3[1]));
							}
						}
					}
				}
			}
		}


		return answer;
	}
}

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