Stockroom reconcile

Reconcile a store's stock ledger with the physical count taken overnight and report only the discrepancies that matter.

Both inputs are lists of strings "sku quantity": a SKU code (letters and digits) and a whole number of units. SKU codes are case-insensitive (ab12 and AB12 are the same item) and are reported in uppercase. A SKU may appear on several lines of the same list, for example a count made on several shelves; add those quantities up.

For a SKU that is in ledger, the allowed tolerance is the larger of tol_units and ledger_total * tol_percent // 100 (integer division). A SKU missing from the count has a counted total of 0. The variance is counted - ledger; it is acceptable if its absolute value is at most the tolerance, and then nothing is reported.

Otherwise report:

• "SKU SHORT n" if fewer units were counted than the ledger says, n being the shortfall;
• "SKU OVER n" if more were counted, n being the surplus.

A SKU that appears in the count but nowhere in the ledger is reported as "SKU UNKNOWN n" with n its counted total, whatever the tolerance, unless that total is 0. A SKU that is in the ledger with a total of 0 is a known SKU.

Input: ledger and counted, lists of strings in the format above, and the integers tol_units and tol_percent.

Output: the report lines, ordered by n descending and, for equal n, by SKU in ascending string order. If everything is within tolerance, return [].