{"id":"valid-palindrome-uses-o1-space","text":"`isPalindrome` uses O(1) auxiliary space via two-pointer inward sweep; it never allocates a filtered or reversed copy of the input string.","truth_value":"IN","source":"entries/2026/06/06/valid-palindrome-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"valid-palindrome-uses-o1-space","truth_value":"IN","reason":"premise"}]}}