Reverse a String

Problem

You are given a string s. You need to reverse the string.

Examples:

Example 1:

Input:
s = Geeks
Output: skeeG

Example 2:

Input:
s = for
Output: rof

Your Task:

You only need to complete the function reverseWord() that takes s as parameter and returns the reversed string.

• Expected Time Complexity: $O(|S|)$
• Expected Auxiliary Space: $O(1)$

Constraints:

$1 <= |s| <= 10000$

Solution

Python

def reverseWord(self, str: str) -> str:
    str = str[::-1]
    return str

Java

public static String reverseWord(String str) {
        char ch;
        String nstr = "";
        for (int i=0; i<str.length(); i++) {
            ch = str.charAt(i); 
            nstr = ch+nstr; 
        }
        return nstr;
}

C++

public:
string reverseWord(string str) {
    int left = 0;
    int right = str.length() - 1;
    while (left < right) {
        swap(str[left], str[right]);
        left++;
        right--;
    }
    return str;
}

C

void reverseWord(char *str) {
    int left = 0;
    int right = strlen(str) - 1;
    char temp;
    while (left < right) {
        temp = str[left];
        str[left] = str[right];
        str[right] = temp;
        left++;
        right--;
    }
}

• Time Complexity: $O(n)$
• Auxiliary Space: $O(1)$