Given a string containing n numbers of words. The task is to swap the corner words of the string and reverses all the middle characters of the string.
Input: "Hello this is the GFG user" Output: "user GFG eth si siht Hello" Input: "Hello Bye" Output: "Bye Hello"
Methods:
- Using the concept of ASCII values
- Using the split() method
Method 1: Using the concept of ASCII values
We handle the position of space between the words using ASCII values. The ASCII value of space is 32.
- Create two string variables and two pointers lets name as index and index1
- Iterate the first loop using the index address variable till the first space and store all the characters in a string variable named First.
- Iterate another loop from reverse order using the index1 address variable till the first space and store all the characters in another string variable name as last.
- Now, we have the address variables index1 and index that both point to the next starting and ending position of the middle characters of the given string.
- Using both pointers store all the characters in reverse order in a third-string variable named as middle.
- Print the last string then the middle string then the first string.
Example:
Java
// Java Program to Swap Corner Words and Reverse Middle// Characters// Importing utility classesimport java.util.*;// Importing input output classesimport java.io.*;// Main classpublic class GFG { // Method 1 // To swap corners words static void swap(String m, int length) { // Declaring string variables to // store the first and last characters String first = ""; String last = ""; // Creating first address variable // Initially initializing with zero int index = 0; for (index = 0; index < length; ++index) { // Checking the space if (m.charAt(index) == 32) { break; } // Storing the last word in the last variable last += m.charAt(index); } // Now creating second address variable // Initially initializing with zero int index1 = 0; for (index1 = length - 1; index1 >= 0; --index1) { if (m.charAt(index1) == 32) { break; } // Storing the First word of the given string first = m.charAt(index1) + first; } String middle = ""; for (int i = index1 - 1; i > index; --i) { if (m.charAt(i) == 32) { middle += " "; } else { // Storing all the middle words middle += m.charAt(i); } } // Print and display all the string variables System.out.print(first + " " + middle + " " + last); } // Method 2 // Main driver method public static void main(String[] args) { // Given custom input string String m = "Hello this is the GFG"; // Calculating string length using length() method // and storing it in a variable int length = m.length(); // Calling the method 1 to swap the words // for our custom input string swap(m, length); }} |
Output
GFG eht si siht Hello
Time Complexity: O(n) where n is the length of the string
Auxiliary Space: O(1)
Method 2: Using the split() method
The string split() method breaks a given string around matches of the given regular expression.
Illustration:
Input : 016-78967
Processing : Regular Expression
Output : {"016", "78967"}
Procedure:
- Store all the words in an array using split() method.
- Swap the last and first element of the array.
- Iterate the loop from the second position to the last second position.
- Store all the characters in the reverse order name as the middle variable.
- Print the first element of the array then the middle variable then the last element of the array.
Example:
Java
// Java Program to Swap Corner Words and Reverse Middle// Characters// Importing utility classes// Importing input output classesimport java.io.*;import java.util.*;// Main classpublic class GFG { // Method 1 // To swap the words in a string static void swap(String m, int length) { // Storing the words in the array String msg[] = m.split(" "); // Now swap the position of the first and the last // character in the string array String temp = msg[0]; msg[0] = msg[msg.length - 1]; msg[msg.length - 1] = temp; // Declaring and initializing string for // middle string empty middle string String mid = ""; for (int i = msg.length - 2; i >= 1; --i) { String temp_s = msg[i]; // Now storing the middle words in reverse order for (int j = temp_s.length() - 1; j >= 0; --j) { mid += temp_s.charAt(j); } mid += " "; } // Lastly print the swapped and reversed words System.out.print(msg[0] + " " + mid + " " + msg[msg.length - 1]); } // Method 2 // Main driver method public static void main(String[] args) { // Custom input string String m = "Hello this is the GFG"; // Calculating length using length() method and // storing it int length = m.length(); // Calling the method 1 over custom input string to // get swapped corner words with reverse middle // characters swap(m, length); }} |
Output
GFG eht si siht Hello
Time Complexity: O(n) where n is the length of the string
Auxiliary Space: O(n) where n is the length of the string
