Reverse String With Spaces

You are given a string s that contains letters, spaces, and special characters. Your task is to reverse the characters of the string while keeping the spaces in their original positions. In other words, only the non-space characters should be reversed, while the spaces should remain at the same indices as in the input.

Note: The input may contain leading, trailing, or multiple consecutive spaces. Your solution must handle these cases correctly.

The reversal should follow the algorithm where two pointers traverse the string from both ends. If a pointer encounters a space, it should skip that character and continue. Otherwise, swap the non-space characters.

inputFormat

The input consists of a single line containing the string s. The string may include spaces as well as special characters. Input is provided via standard input (stdin).

outputFormat

Output the modified string after reversing only the non-space characters, keeping spaces in their original positions. The output should be written to standard output (stdout).

hello world

dlrow olleh