Welcome to Subscribe On Youtube

709. To Lower Case

Description

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

 

Example 1:

Input: s = "Hello"
Output: "hello"

Example 2:

Input: s = "here"
Output: "here"

Example 3:

Input: s = "LOVELY"
Output: "lovely"

 

Constraints:

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

Solutions

Solution 1: Direct Implementation

We can loop through the string and for each uppercase letter, convert it to lowercase. Finally, the converted string is returned.

Time complexity $O(n)$, where $n$ is the length of the string. Ignoring the space consumption of the answer, the space complexity is $O(1)$.

Solution 2

This implementation follows the required operations directly. A keyed container records values that must be found or updated efficiently. After all required states have been considered, the maintained result is returned.

• Java
• C++
• Python
• Go
• TypeScript
• Rust
• C

• class Solution {
      public String toLowerCase(String s) {
          char[] cs = s.toCharArray();
          for (int i = 0; i < cs.length; ++i) {
              if (cs[i] >= 'A' && cs[i] <= 'Z') {
                  cs[i] |= 32;
              }
          }
          return String.valueOf(cs);
      }
  }
  

• class Solution {
  public:
      string toLowerCase(string s) {
          for (char& c : s) {
              if (c >= 'A' && c <= 'Z') {
                  c |= 32;
              }
          }
          return s;
      }
  };
  

• class Solution:
      def toLowerCase(self, s: str) -> str:
          return "".join([chr(ord(c) | 32) if c.isupper() else c for c in s])
  
  

• func toLowerCase(s string) string {
  	cs := []byte(s)
  	for i, c := range cs {
  		if c >= 'A' && c <= 'Z' {
  			cs[i] |= 32
  		}
  	}
  	return string(cs)
  }
  

• function toLowerCase(s: string): string {
      return [...s].map(c => String.fromCharCode(c.charCodeAt(0) | 32)).join('');
  }
  
  
  // Solution 2
  function toLowerCase(s: string): string {
      return [...s].map(c => String.fromCharCode(c.charCodeAt(0) | 32)).join('');
  }
  
  

• impl Solution {
      pub fn to_lower_case(s: String) -> String {
          s.as_bytes()
              .iter()
              .map(|&c| char::from(if c >= b'A' && c <= b'Z' { c | 32 } else { c }))
              .collect()
      }
  }
  
  
  // Solution 2
  impl Solution {
      pub fn to_lower_case(s: String) -> String {
          s.as_bytes()
              .iter()
              .map(|&c| char::from(if c >= b'A' && c <= b'Z' { c | 32 } else { c }))
              .collect()
      }
  }
  
  

• char* toLowerCase(char* s) {
      int n = strlen(s);
      for (int i = 0; i < n; i++) {
          if (s[i] >= 'A' && s[i] <= 'Z') {
              s[i] |= 32;
          }
      }
      return s;
  }
  

All Problems

All Solutions