Solve these string, subset, and date problems
Quick Overview
This multi-part question evaluates string and array manipulation, in-place algorithm implementation, combinatorial subset generation with and without duplicate handling, and calendar date arithmetic, testing competencies in algorithm design, complexity analysis, and edge-case handling within the Coding & Algorithms domain and requiring both conceptual understanding and practical implementation skills. Such problems are commonly asked in technical interviews to gauge a candidate's ability to implement efficient algorithms, reason about permutations and deduplication, manage memory constraints for in-place operations, and correctly handle date calculations and input edge cases.
You are asked to solve multiple coding tasks.
- Reverse word order in a string
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Input: a string
scontaining words separated by spaces (may contain leading/trailing spaces and multiple spaces between words). - Output: a string where the order of words is reversed , with exactly one space between words, and no leading/trailing spaces .
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Example:
" the sky is blue " -> "blue is sky the"
Follow-up: If the input is a mutable character array (e.g., char[]), modify it in place (O(1) extra space) to achieve the same result.
- All subsets (no duplicates in input)
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Input: an integer array
numswhere all elements are distinct. - Output: return all possible subsets (the power set). Order does not matter.
- All unique subsets (duplicates allowed in input)
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Input: an integer array
numsthat may contain duplicates. - Output: return all unique subsets (no duplicate subsets in the output).
- Days between two dates
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Input: two dates
date1anddate2in the formatYYYY-MM-DD. - Output: return the absolute number of days between the two dates.
- Assume valid Gregorian calendar dates.