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++ program for creating a string // by alternately combining the // characters of two halves // in reverse #include <bits/stdc++.h> using namespace std;
// Function performing calculations 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
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 code int main()
{ string s = "sunshine" ;
// Calling function
solve(s);
return 0;
} |
// Java program for creating a string // by alternately combining the // characters of two halves // in reverse import 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);
}
} |
# Python 3 program for creating a string # by alternately combining the # characters of two halves # in reverse # Function performing calculations def 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 code s = "sunshine"
# Calling function solve(s) # This code is contributed by Nikita Tiwari |
// 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 // Python 3 program for creating a string // by alternately combining the // characters of two halves in reverse // Function performing calculations function 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 function solve( $s );
// This code is contributed // by ChitraNayal ?> |
<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> |
sennuish
Time complexity: O(n) where n is the length of the string
Auxiliary Space: O(n)