A method can include identifying, by processing circuitry of a device, a row of rows and/or column of columns to which a first feature and a second feature of an input maps, comparing the identified row and/or column to a row run length encoding (RLE) in a memory of the device that indicates, for each row, whether one or more cells in the row include an input mapped thereto or a column RLE in a memory of the device that indicates, for each column, whether one or more cells in the column include an input mapped thereto, respectively, and determining the input data is anomalous in response to determining either the row RLE indicates that no inputs are mapped to the row to which the input maps, or the column RLE indicates that no inputs are mapped to the column to which the input maps.