709. To Lower Case

1. Description

Given a string s, return the string after replacing every uppercase letter with the same lowercase letter.

2. Example

Example 1:
Input: s = “Hello”
Output: “hello”

Example 2:
Input: s = “here”
Output: “here”

Example 3:
Input: s = “LOVELY”
Output: “lovely”

3. Constraints

• 1 <= s.length <= 100
• s consists of printable ASCII characters.

4. Solutions

Bit Manipulation

n = str.size()
Time complexity: O(n)
Space complexity: O(n)

class Solution {
public:
    string toLowerCase(string &str) {
        for(int i = 0; i < str.size(); ++i) {
            if('A' <= str[i] && str[i] <= 'Z') {
                str[i] |= 32;
            }
        }

        return str;
    }
};