Added Useful Links

Author: abhiabhi

src/main/java/com/string/DefangingAnIpAddress.java

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+package com.string;
+
+/**
+ * Given a valid (IPv4) IP address, return a defanged version of that IP address.
+ *
+ * A defanged IP address replaces every period "." with "[.]".
+ *
+ * Example 1:
+ *
+ * Input: address = "1.1.1.1"
+ * Output: "1[.]1[.]1[.]1"
+ * Example 2:
+ *
+ * Input: address = "255.100.50.0"
+ * Output: "255[.]100[.]50[.]0"
+ */
+public class DefangingAnIpAddress {
+
+    public static void main (String args[]){
+       String s =  defangIPaddr("198.100.100.100");
+        System.out.println(s);
+    }
+
+    public static String defangIPaddr(String address) {
+        StringBuilder sb = new StringBuilder();
+        for (char c : address.toCharArray()) {
+            if (c == '.') {
+                sb.append("[.]");
+            }
+            else {
+                sb.append(c);
+            }
+        }
+
+        return sb.toString();
+    }
+}

src/main/java/com/string/RemoveVowelsFromString.java

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+package com.string;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+public class RemoveVowelsFromString {
+
+    public static void main(String args[]) {
+        String input = "hello";
+        StringBuilder output = removeVowels(input);
+        System.out.println(output);
+    }
+
+    private static StringBuilder removeVowels(String input) {
+        Set<Character> vowelSet = new HashSet<>(Arrays.asList('a', 'e', 'i', 'o', 'u'));
+        StringBuilder output = new StringBuilder();
+        for (Character c : input.toCharArray()) {
+            if (!vowelSet.contains(c)) {
+                output.append(c);
+            }
+        }
+        return output;
+
+    }
+}

src/main/java/com/theory/UsefulLinks

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+https://cheatsheet.dennyzhang.com/cheatsheet-leetcode-A4