Problem Description
Given a string s, return the last substring of s in lexicographical order.
Key Insights
- The problem requires finding the lexicographically maximum substring from all possible substrings of a given string.
- A naive approach would involve generating all substrings and then sorting them, which is computationally expensive.
- Instead, we can use a more efficient algorithm involving two pointers to track the maximum lexicographical substring while iterating through the string.
Space and Time Complexity
Time Complexity: O(n)
Space Complexity: O(1)
Solution
To solve the problem, we can utilize a single traversal of the string with two pointers. The idea is to maintain a start index for the maximum substring found so far and compare the current character with the maximum substring's character. If the current character is greater, we update our maximum substring start index. This approach ensures we only need to traverse the string once, yielding an optimal solution.