1323. Maximum 69 Number ¶ Time: $O(\log\texttt{num})$ Space: $O(\log\texttt{num})$ C++JavaPython 1 2 3 4 5 6 7 8 9 10 11 12 13 14class Solution { public: int maximum69Number(int num) { string ans = to_string(num); for (char& c : ans) if (c == '6') { c = '9'; break; } return stoi(ans); } }; 1 2 3 4 5 6 7 8 9 10 11 12 13class Solution { public int maximum69Number(int num) { char[] ans = String.valueOf(num).toCharArray(); for (int i = 0; i < ans.length; ++i) if (ans[i] == '6') { ans[i] = '9'; break; } return Integer.valueOf(String.valueOf(ans)); } } 1 2 3class Solution: def maximum69Number(self, num: int) -> int: return int(str(num).replace('6', '9', 1))