First, clarify the problem constraints and edge cases, then outline a greedy line-packing algorithm that determines how many words fit per line. For each line except the last, distribute spaces evenly with extra spaces on the left; for the last line, left-justify with single spaces. Finally, discuss time/space complexity and potential optimizations.
Pro tip: Mention that you would handle edge cases like a single word exceeding the max width or empty input, and that you'd test with examples to ensure correct space distribution. This shows attention to detail and robustness.
Ask about input constraints (e.g., word length vs. maxWidth, empty array) and confirm the justification rules, especially for the last line and extra spaces.
Iterate through words, accumulating characters and spaces to determine the maximum number of words that fit in each line without exceeding maxWidth.
For each line except the last, calculate total spaces needed, then distribute evenly with extra spaces assigned to the leftmost gaps. For the last line, join words with a single space and pad with trailing spaces.
Write clean code, then walk through test cases like ["This", "is", "an", "example", "of", "text", "justification."] with maxWidth=16 to verify correctness.
State that the algorithm runs in O(n) time where n is total characters, and O(1) extra space excluding output. Mention potential optimizations like precomputing word lengths.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Use a greedy approach with a range of possible open parenthesis counts, updating the range as you process each character. At the end, check if 0 is within the range; if so, the string can be balanced. To return a valid assignment, do a second pass using a stack or backtracking to assign '*' characters appropriately.
Pro tip: Discuss both the greedy range method for feasibility and a backtracking method for constructing an assignment, showing you understand trade-offs between time and space. Mention that the greedy method runs in O(n) time and O(1) space, which is optimal.
Confirm that '*' can be '(', ')', or empty, and that we need to determine if any assignment yields a balanced sequence. Ask if returning one valid assignment is required or just a boolean.
Maintain a range [low, high] of possible open parenthesis counts. For '(', increment both; for ')', decrement both (clamp low to 0); for '*', decrement low (clamp to 0) and increment high. At the end, check if low == 0.
If a valid assignment is required, use a stack to track indices of '(' and '*'. First pass: match ')' with '(' or '*'. Second pass: match remaining '(' with '*' to the right. Replace unmatched '*' with empty string.
State that the greedy feasibility check runs in O(n) time and O(1) space. The construction method also runs in O(n) time but uses O(n) space for the stack.
Walk through examples like '(*)' (valid), '(*))' (invalid), and '**' (valid) to demonstrate correctness and edge cases.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Use BFS to find the shortest path in an unweighted grid, tracking parent pointers to reconstruct the path. First validate inputs (start/end in bounds and not blocked), then run BFS from start to end, and finally backtrack from end to start to build the path list.
Pro tip: Mention that BFS guarantees the shortest path in unweighted grids, and proactively discuss edge cases like start == end, no path, and invalid inputs. Also, note that using a visited set or modifying the grid in-place can optimize space.
Check if start and end coordinates are within grid bounds and not obstacles. If invalid, return an empty list immediately.
Initialize a queue with the start cell, a visited set to avoid revisiting, and a parent map (or 2D array) to track the path.
While the queue is not empty, dequeue a cell, check if it's the end, and if not, enqueue all valid unvisited neighbors (up, down, left, right).
If the end is reached, backtrack from end to start using the parent map to construct the path, then reverse it to get start-to-end order.
If BFS completes without reaching the end, return an empty list. Otherwise, return the reconstructed path.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.