Leet Code

Leet Code Problems

Problem	Quick Solution	Brute Force	Time Optimized	Space Optimized
Palindrome	O(n) time, O(n) space. Use regex to clean string, convert to lowercase, and compare with its reverse.	O(n) time, O(n) space. Clean string by removing non-alphanumeric chars and converting to lowercase. Compare characters from start and end.	O(n) time, O(1) space. Two-pointer approach, skipping non-alphanumeric chars and doing case-insensitive comparison.	O(n) time, O(1) space. Two-pointer approach, in-place comparison without creating additional strings or character arrays.