/** * @param {*[][]} originalMatrix * @return {*[][]} */ export default function squareMatrixRotation(originalMatrix) { const matrix = originalMatrix.slice(); // Do top-right/bottom-left diagonal reflection of the matrix. for (let rowIndex = 0; rowIndex < matrix.length; rowIndex += 1) { for (let columnIndex = rowIndex + 1; columnIndex < matrix.length; columnIndex += 1) { // Swap elements. [ matrix[columnIndex][rowIndex], matrix[rowIndex][columnIndex], ] = [ matrix[rowIndex][columnIndex], matrix[columnIndex][rowIndex], ]; } } // Do horizontal reflection of the matrix. for (let rowIndex = 0; rowIndex < matrix.length; rowIndex += 1) { for (let columnIndex = 0; columnIndex < matrix.length / 2; columnIndex += 1) { // Swap elements. [ matrix[rowIndex][matrix.length - columnIndex - 1], matrix[rowIndex][columnIndex], ] = [ matrix[rowIndex][columnIndex], matrix[rowIndex][matrix.length - columnIndex - 1], ]; } } return matrix; }