{"id":"missing-number-gauss-sum","text":"`missing-number/solution.py` uses Gauss's formula `n*(n+1)//2 - sum(nums)` for O(n) time and O(1) space, rather than XOR, hash set, or sorting approaches.","truth_value":"IN","source":"entries/2026/06/06/missing-number-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"missing-number-gauss-sum","truth_value":"IN","reason":"premise"}]}}