To Lower Case Python Solution with Tests

Tested Python solution for LeetCode 709 with 16 pytest cases. Generate a practice environment with lcpy.

LeetCode 709, Easy. Topics: String. View on LeetCode.

Generate this problem as a practice environment: tested reference solution, 16 parametrized pytest cases, and a playground notebook:

lcpy gen -n 709   # by problem number
lcpy gen -s to_lower_case   # by problem name

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Problem

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

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Examples

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

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

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

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Constraints

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

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Solution

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

class Solution:
    # Time: O(n)
    # Space: O(n)
    def to_lower_case(self, s: str) -> str:
        out: list[str] = []
        for ch in s:
            code = ord(ch)
            out.append(chr(code + 32) if 65 <= code <= 90 else ch)
        return "".join(out)

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Complexity

Time	Space
O(n)	O(n)

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