Added: Hackerrank/JavaRegex.java

Hackerrank/JavaRegex.java

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+// Write a class called MyRegex which will contain a string pattern. You need to write a regular expression and assign it to the pattern such that it can be used to validate an IP address. Use the following definition of an IP address:
+
+// IP address is a string in the form "A.B.C.D", where the value of A, B, C, and D may range from 0 to 255. Leading zeros are allowed. The length of A, B, C, or D can't be greater than 3.
+// Some valid IP address:
+
+// 000.12.12.034
+// 121.234.12.12
+// 23.45.12.56
+// Some invalid IP address:
+
+// 000.12.234.23.23
+// 666.666.23.23
+// .213.123.23.32
+// 23.45.22.32.
+// I.Am.not.an.ip
+// In this problem you will be provided strings containing any combination of ASCII characters. You have to write a regular expression to find the valid IPs.
+
+// Just write the MyRegex class which contains a String . The string should contain the correct regular expression.
+
+// (MyRegex class MUST NOT be public)
+
+// Sample Input
+
+// 000.12.12.034
+// 121.234.12.12
+// 23.45.12.56
+// 00.12.123.123123.123
+// 122.23
+// Hello.IP
+// Sample Output
+
+// true
+// true
+// true
+// false
+// false
+// false
+
+
+// Code in Java
+
+import java.io.*;
+import java.sql.SQLOutput;
+import java.util.*;
+
+public class Solution {
+
+    public static boolean Checker(String str){
+        boolean check = true;
+        int len = str.length(), Count = 0;
+        if (len > 15){
+            return false;
+        }
+        for(int i = 0 ; i < len; i++){
+            if(!Character.isDigit(str.charAt(i))){
+                if(str.charAt(i) != '.') {
+                    return false;
+                }
+            }
+            if(str.charAt(i) == '.'){
+                Count++;
+            }
+        }
+
+        if(Count != 3) {
+            return false;
+        }
+        int num;
+        Count = 0;
+        for(int i = 0; i < len ;i++){
+            for(int j = i; j < len ; j++){
+                if(str.charAt(j) == '.'){
+                    num = Integer.parseInt(str.substring(i, j));
+                    Count++;
+                    i = j;
+                    if(num < 0 || num > 255) {
+                        return false;
+                    }
+
+                    if(Count == 3){
+                        num = Integer.parseInt(str.substring(j+1, str.length()));
+                        if(num < 0 || num > 255) {
+                            return false;
+                        }
+                    }
+                    i++;
+
+                }
+            }
+        }
+        return check;
+    }
+    public static void main(String[] args) {
+        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
+        Scanner scan = new Scanner(System.in);
+
+        while(scan.hasNext()){
+            String ipAddress = scan.next();
+            if(Checker(ipAddress)){
+                System.out.println("true");
+            }else{
+                System.out.println("false");
+            }
+        }
+
+    }
+}