✅ One Line Solution
Code #1\nTime complexity: O(n). Space complexity: O(1).\n\nclass Solution:\n    def countSeniors(self, a: List[str]) -> int:\n        return sum(s[11:13]>\'60\'
# Code #1\nTime complexity: $$O(n)$$. Space complexity: $$O(1)$$.\n```\nclass Solution:\n    def countSeniors(self, a: List[str]) -> int:\n        return sum(s[11:13]>\'60\' for s in a)\n```\n\n# Code #2\nTime complexity: $$O(n)$$. Space complexity: $$O(1)$$.\n```\nclass Solution:\n    def countSeniors(self, a: List[str]) -> int:\n        return len([*filter(lambda s:s[11:13]>\'60\',a)])\n```\n\n# Code #3\nTime complexity: $$O(n)$$. Space complexity: $$O(1)$$.\n```\nclass Solution:\n    def countSeniors(self, a: List[str]) -> int:\n        return sum(map(gt,map(itemgetter(11,12),a),repeat((\'6\',\'0\'))))\n```
['Array', 'String', 'Python', 'Python3']