Given a string s, create a new string such that it contains the characters of the two halves of the string s combined alternately in reverse order.
Examples:
Input : s = carbohydrates
Output : hsoebtraarcdyInput : s = sunshine
Output : sennuish
Explanation:
Example 1: Two halves of the string carbohydrate are carboh and ydrates. As they needed to be added in reverse alternately, start with h from first half then s from second half followed by o from first half, e from second half and so on. The string p comes out to be hsoebtraarcdy. If one of the string is completely finished then simply add the remaining characters of the other string in reverse order.
Example 2: The two halves of the string are suns and hine. String sennuish is the desired string p.
Algorithm:
- Define a method named “solve” of void return type which takes string “s” as an input parameter.
- Create three int variables named “l”, “x”, and “y” and initialize them with a length of the string, half the length of the string, and the length of the string respectively.
- Define an empty string variable “p” to store the final output string.
- Start a while loop, and iterate until variable “x” is greater than 0 and variable “y” is greater than l/2.
- get the character at index (x-1) and add it to string “p”. Then, decrement the value of “x”.
- Again, get the character at index (y-1) and add it to string “p”. Then, decrement the value of “y”.
- If “y” is greater than l/2, then get the character at index (y-1) and add it to string “p”.
- Then, decrement the value of “y”.
- Finally, print the string “p”.
Implementation:
C++
// C++ program for creating a string // by alternately combining the// characters of two halves // in reverse #include <bits/stdc++.h>using namespace std;// Function performing calculationsvoid solve(string s){ int l = s.length(); int x = l / 2; int y = l; // Calculating the two halves // of string s as first and // second. The final string p string p = ""; while (x > 0 && y > l / 2) { // It joins the characters to // final string in reverse order p += s[x - 1]; x--; // It joins the characters to // final string in reverse order p += s[y - 1]; y--; } if (y > l / 2) { p += s[y - 1]; y--; } cout << p;}// Driver codeint main(){ string s = "sunshine"; // Calling function solve(s); return 0;} |
Java
// Java program for creating a string// by alternately combining the// characters of two halves// in reverseimport java.io.*;class GFG { // Function performing calculations public static void solve(String s) { int l = s.length(); int x = l / 2; int y = l; // Calculating the two halves of // string s as first and second // The final string p String p = ""; while (x > 0 && y > l / 2) { // It joins the characters to // final string in reverse order char ch = s.charAt(x - 1); p += ch; x--; // It joins the characters to // final string in reverse order ch = s.charAt(y - 1); p += ch; y--; } if (y > l / 2) { char ch = s.charAt(y - 1); p += ch; y--; } System.out.println(p); } // Driver method public static void main(String args[]) { String s = "sunshine"; // Calling function solve(s); }} |
Python3
# Python 3 program for creating a string # by alternately combining the# characters of two halves # in reverse # Function performing calculationsdef solve(s) : l = len(s) x = l // 2 y = l # Calculating the two halves # of string s as first and # second. The final string p p = "" while (x > 0 and y > l / 2) : # It joins the characters to # final string in reverse order p = p + s[x - 1] x = x - 1 # It joins the characters to # final string in reverse order p = p + s[y - 1] y = y - 1 if (y > l // 2) : p = p + s[y - 1] y = y - 1 print (p)# Driver codes = "sunshine"# Calling functionsolve(s)# This code is contributed by Nikita Tiwari |
C#
// C# program for creating a string // by alternately combining the// characters of two halves // in reverse using System;class GFG { // Function performing calculations public static void solve(string s) { int l = s.Length; int x = l / 2; int y = l; // Calculating the two halves of // string s as first and second // The final string p string p = ""; while (x > 0 && y > l / 2) { // It joins the characters to // final string in reverse order char ch = s[x - 1]; p += ch; x--; // It joins the characters to // final string in reverse order ch = s[y - 1]; p += ch; y--; } if (y > l / 2) { char ch = s[x - 1]; p += ch; y--; } Console.WriteLine(p); } // Driver method public static void Main() { string s = "sunshine"; // Calling function solve(s); }}// This code is contributed by vt_m. |
PHP
<?php // Python 3 program for creating a string // by alternately combining the// characters of two halves in reverse // Function performing calculationsfunction solve($s){ $l = strlen($s); $x = $l / 2; $y = $l; // Calculating the two halves // of string s as first and // second. The final string p $p = ""; while ($x > 0 && $y > $l / 2) { // It joins the characters to // final string in reverse order $p = $p.$s[$x - 1]; $x--; // It joins the characters to // final string in reverse order $p = $p.$s[$y - 1]; $y--; } if ($y > $l / 2) { $p = $p.$s[$y - 1]; $y--; } echo $p;}// Driver code$s = "sunshine"; // Calling functionsolve($s);// This code is contributed// by ChitraNayal?> |
Javascript
<script>// JavaScript program for creating a string // by alternately combining the// characters of two halves // in reverse // Function performing calculations function solve( s) { var l = s.length; var x = l / 2; var y = l; // Calculating the two halves of // string s as first and second // The final string p var p = ""; while (x > 0 && y > l / 2) { // It joins the characters to // final string in reverse order var ch = s.charAt(x - 1); p += ch; x--; // It joins the characters to // final string in reverse order ch = s.charAt(y - 1); p += ch; y--; } if (y > l / 2) { var ch = s.charAt(x - 1); p += ch; y--; } document.write(p); } // Driver method var s = "sunshine"; // Calling function solve(s);// This code is contributed by todaysgaurav </script> |
Output
sennuish
Time complexity: O(n) where n is the length of the string
Auxiliary Space: O(n)
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