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Sep 10, 2017 · 2. One natural way to reverse a String is to use a StringTokenizer and a stack. Stack is a class that implements an easy-to-use last-in, first-out (LIFO) stack of objects. String s = "Hello My name is Sufiyan"; Put it in the stack frontwards. Stack<String> myStack = new Stack<>();
Jan 26, 2010 · Step 2. Increment the start index decrement the end index. Step 3. Iterate Step 1 and Step 2 till start index < end index. For this, the time complexity will be O (n) and the space complexity will be O (1) Sample code for reversing an array in space is like: public static int[] reverseAnArrayInSpace(int[] array) {.
Bozho already gave a great Java-specific answer, but in the event you ever need to solve this problem without Java API methods: To reverse, you can simply pop individual words onto a stack and pop them all back off when there are no words left.
Aug 2, 2016 · 3. Use StringBuilder class or StringBuffer class they have already a method reverse() for reversing the string. StringBuilder str = new StringBuilder("india"); System.out.println("string = " + str); // reverse characters of the StringBuilder and prints it. System.out.println("reverse = " + str.reverse()); // reverse is equivalent to the actual.
The function takes the first character of a String - str.charAt(0) - puts it at the end and then calls itself - reverse() - on the remainder - str.substring(1), adding these two things together to get its result - reverse(str.substring(1)) + str.charAt(0) When the passed in String is one character or less and so there will be no remainder left ...
May 26, 2012 · One can modify the list in place, create a copy in reverse order, or create a view in reversed order. The simplest way, intuitively speaking, is Collections.reverse: Collections.reverse(myList); This method modifies the list in place. That is, Collections.reverse takes the list and overwrites its elements, leaving no unreversed copy behind.
Nov 8, 2009 · It's not directly possible to reverse sort an array of primitives (i.e., int[] arr = {1, 2, 3};) using Arrays.sort() and Collections.reverseOrder() because those methods require reference types (Integer) instead of primitive types (int). However, we can use Java 8 Stream to first box the array to sort in reverse order:
Sep 28, 2010 · Java reverse an int value - Principles. Modding (%) the input int by 10 will extract off the rightmost digit. example: (1234 % 10) = 4. Multiplying an integer by 10 will "push it left" exposing a zero to the right of that number, example: (5 * 10) = 50. Dividing an integer by 10 will remove the rightmost digit. (75 / 10) = 7.
Aug 31, 2020 · First, the easiest solution would be to split() the input and then use Stream logic to combine the words in reverse order, however I consider Stream logic to be "Loop logic", so that won't do. That leaves the use of a recursive method as a solution, similar to the attempt in the question: int idx = input.indexOf(' ');
Apr 10, 2010 · Well, printing itself would suggest a predefined function... Presumably, though, you could obtain the characters and concatenate them manually in reverse (i.e. loop over it backwards). Of course, you could say concatenation is a predefined function... so maybe the char array itself. But again...
