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League Backend Challenge In main.go you will find a basic web server written in GoLang. It accepts a single request /echo. Extend the webservice with the ability to perform the following operations Given an uploaded csv file 1,2,3 4,5,6 7,8,9 Echo (given) Return the matrix as a string in matrix format. // Expected output 1,2,3 4,5,6 7,8,9 Invert Return the matrix as a string in matrix format where the columns and rows are inverted // Expected output 1,4,7 2,5,8 3,6,9 Flatten Return the matrix as a 1 line string, with values separated by commas. // Expected output 1,2,3,4,5,6,7,8,9 Sum Return the sum of the integers in the matrix // Expected output 45 Multiply Return the product of the integers in the matrix // Expected output 362880 The input file to these functions is a matrix, of any dimension where the number of rows are equal to the number of columns (square). Each value is an integer, and there is no header row. matrix.csv is example valid input. Run web server go run . Send request curl -F 'file=@/path/matrix.csv' "localhost:8080/echo" What we're looking for The solution runs The solution performs all cases correctly The code is easy to read The code is reasonably documented The code is tested The code is robust and handles invalid input and provides helpful error messages
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Senior Software Engineer Backend – (Apps & Solutions)

Interviewed at League

3.6★
Feb 24, 2025

League Backend Challenge In main.go you will find a basic web server written in GoLang. It accepts a single request /echo. Extend the webservice with the ability to perform the following operations Given an uploaded csv file 1,2,3 4,5,6 7,8,9 Echo (given) Return the matrix as a string in matrix format. // Expected output 1,2,3 4,5,6 7,8,9 Invert Return the matrix as a string in matrix format where the columns and rows are inverted // Expected output 1,4,7 2,5,8 3,6,9 Flatten Return the matrix as a 1 line string, with values separated by commas. // Expected output 1,2,3,4,5,6,7,8,9 Sum Return the sum of the integers in the matrix // Expected output 45 Multiply Return the product of the integers in the matrix // Expected output 362880 The input file to these functions is a matrix, of any dimension where the number of rows are equal to the number of columns (square). Each value is an integer, and there is no header row. matrix.csv is example valid input. Run web server go run . Send request curl -F 'file=@/path/matrix.csv' "localhost:8080/echo" What we're looking for The solution runs The solution performs all cases correctly The code is easy to read The code is reasonably documented The code is tested The code is robust and handles invalid input and provides helpful error messages

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