This problem asks you to identify the color of a chessboard square based on its coordinates. You can solve it by converting the letter and number into numerical indices and using arithmetic to determine parity. The solution leverages a math plus string pattern, ensuring fast evaluation and minimal computation for any valid input.
Problem Statement
You are given a string representing the coordinates of a square on a standard 8x8 chessboard, such as "a1" or "h8". Determine whether the square is white or black by analyzing its position.
Return true if the square is white and false if it is black. The input will always be a valid chessboard coordinate with a letter first (from 'a' to 'h') and a number second (from '1' to '8').
Examples
Example 1
Input: coordinates = "a1"
Output: false
From the chessboard above, the square with coordinates "a1" is black, so return false.
Example 2
Input: coordinates = "h3"
Output: true
From the chessboard above, the square with coordinates "h3" is white, so return true.
Example 3
Input: coordinates = "c7"
Output: false
Example details omitted.
Constraints
- coordinates.length == 2
- 'a' <= coordinates[0] <= 'h'
- '1' <= coordinates[1] <= '8'
Solution Approach
Convert letter to numeric index
Map the first character of the coordinate to a number from 1 to 8 (e.g., 'a' → 1, 'b' → 2) to align with column indices. This simplifies later parity checks.
Check row parity
Convert the second character (number) directly into an integer representing the row. Combine it with the column index to calculate whether the sum is even or odd.
Determine color using sum parity
Add the numeric column and row indices. If the sum is even, the square is black; if odd, the square is white. Return the boolean result accordingly.
Complexity Analysis
| Metric | Value |
|---|---|
| Time | Depends on the final approach |
| Space | Depends on the final approach |
Time complexity is O(1) because coordinate conversion and arithmetic are constant operations. Space complexity is O(1) as only a few integer variables are needed.
What Interviewers Usually Probe
- The candidate understands converting characters to numeric indices for computation.
- They identify that parity determines the chessboard color pattern.
- They correctly handle the mapping of letters 'a' to 'h' to numerical values without off-by-one errors.
Common Pitfalls or Variants
Common pitfalls
- Misinterpreting the color mapping by reversing black and white parity.
- Off-by-one errors when converting letters to numbers ('a' vs 1).
- Ignoring that the sum of indices, not individual indices, determines the color.
Follow-up variants
- Determine color for a rectangular chessboard of arbitrary size using the same parity approach.
- Return the color as a string 'white' or 'black' instead of a boolean.
- Given multiple coordinates, compute an array of boolean results for all squares efficiently.
How GhostInterview Helps
- GhostInterview instantly converts string coordinates to numeric indices for rapid evaluation.
- It highlights parity checks to correctly distinguish white and black squares, preventing common off-by-one errors.
- It provides immediate feedback on edge cases like 'a1' or 'h8' for consistent boolean outputs.
Topic Pages
Related GhostInterview Pages
- LeetCode Interview Copilot - Use GhostInterview as a live solver when you want direct help with LeetCode-style coding questions.
- Coding Interview Assistant - See how GhostInterview supports array, string, linked list, graph, and tree interview workflows.
- How GhostInterview Works - Review the screenshot, reasoning, and answer flow before using the solver in a live interview.
FAQ
How do I convert a chessboard letter to a number in this problem?
Map letters 'a' to 'h' to numbers 1 through 8, which allows you to compute sums for parity checking.
Why does adding row and column indices determine the square color?
Because the chessboard alternates colors, the sum of column and row indices being even or odd directly maps to black or white squares.
Can this approach handle multiple coordinates at once?
Yes, convert each coordinate individually and apply the sum parity logic to compute a boolean array of results.
What pattern does this problem illustrate?
This is a Math plus String pattern where string parsing is combined with numeric calculations to evaluate parity.
What are common mistakes when implementing this solution?
Reversing the color logic, off-by-one errors in letter-to-number conversion, or summing indices incorrectly.
Need direct help with Determine Color of a Chessboard Square instead of spending more time grinding it?
Download GhostInterview when you want a LeetCode solver, not another long practice loop. Capture Determine Color of a Chessboard Square from a screenshot, get the answer path and complexity, and use supported stealth workflows that stay outside captured layers.
Capture the prompt fast instead of rewriting the problem by hand.
Get the solution path, trade-offs, and complexity summary in one pass.
Stay outside captured layers on supported screen-share workflows.
Stay in the same pattern family
Calculate the minimum operations to sort a string using combinatorial math and string manipulation techniques efficiently.
Open problem page#1759 Count Number of Homogenous SubstringsThis problem requires counting all homogenous substrings in a given string and returning the result modulo 10^9 + 7.
Open problem page#1896 Minimum Cost to Change the Final Value of ExpressionDetermine the minimum operations to change a boolean expression's result using state transition dynamic programming efficiently.
Open problem page