Data Encoding

• All command inputs are provided as strings.
• Menu items are encoded as strings: "itemName:price" (example: "burger:120").
• Item lists are encoded as comma-separated strings inside a command (example: "burger,pizza").

Methods

1) Process Commands

List<String> processCommands(List<String> commands)

• commands.size() >= 0
• Each command parameter is separated by |
• Each command must start with a numeric timestamp.
• All commands must be executed in increasing timestamp order.
• If two commands have the same timestamp, preserve their relative input order.
• The return value is a list of outputs, one output per input command (same length as commands).

2) Get Items Served Per Restaurant

List<String> getRestaurantItemCounts()

• Returns aggregated counts of items served (i.e. dispatched) per restaurant in food orders.
• Each row is encoded as: "restaurantId|itemName|count"
• Ordering of rows: sort lexicographically in ascending order.

3) Get All Dispatched Orders

List<String> getDispatchedOrders(String restaurantId)

• Returns all dispatched orders in the exact order they were dispatched.
• Each row is encoded as: "dispatchTimestamp|orderId|customerId|items"
• items is a comma-separated list (example: "burger,pizza").

Command Format

A) Add / Onboard Restaurant

• capacity is the maximum number of concurrent open (not yet dispatched) orders the restaurant can hold.
• menu is a comma-separated list of "item:price" entries.
• Example: 101|ADD_RESTAURANT|R1|2|burger:120,pizza:200
• Output: OK if added, else RESTAURANT_ALREADY_EXISTS.

B) Update Restaurant Menu / Prices

• menuUpdates is a comma-separated list of "item:price" entries.
• If price >= 0, upsert (add or update) the item price.
• If price < 0, remove the item from existing menu (if present).
• If an item is present in existing menu but not in menuUpdates then it will remain unaffected.
• Example: 105|UPDATE_MENU|R1|burger:130,pasta:150,salad:-1
• Output: OK if updated, else RESTAURANT_NOT_FOUND.

C) Place Order

• items is a comma-separated list of item names (example: "burger,pizza").
• An order is accepted only if we can chose a restaurant based on strategy and:
  • Restaurant has all requested items on its menu at that time, and
  • Restaurant has available capacity (openOrders < capacity).
• Output: ACCEPTED, else REJECTED if no restaurant can be found or INVALID_STRATEGY if strategy doesn't exist.

Restaurant Selection Strategy

• LOWEST_TOTAL_PRICE: pick the restaurant with minimum total price of requested items. Tie-breakers (in order):
  • Higher remaining capacity (capacity - openOrders)
  • Lexicographically smaller restaurantId
• MAX_REMAINING_CAPACITY: pick the restaurant with maximum remaining capacity. Tie-breakers:
  • Lower total price
  • Lexicographically smaller restaurantId
• If strategy is unknown: output INVALID_STRATEGY.

D) Dispatch Order

• Dispatching completes the order, frees up 1 capacity slot for that restaurant, and increments item served counts.
• Output: DISPATCHED, or INVALID_ORDER, or ALREADY_DISPATCHED.

Output Rules

• processCommands must return exactly one output string per command, in the same order as the input command list.
• Even though commands are executed after sorting by timestamp, outputs are returned aligned to the original input positions.

Constraints

• 0 <= timestamp <= 10^12
• 0 <= commands.size() <= 100000
• 1 <= capacity <= 100000
• 0 <= price <= 10^9 (negative price only allowed in UPDATE_MENU to remove an item)
• Restaurant and item names are non-empty and do not contain | or , characters.
• No database, no UI: store everything in memory using appropriate data structures.

Examples

Example 1: Commands given in random timestamp order

• "200|PLACE_ORDER|O1|C1|LOWEST_TOTAL_PRICE|burger,pizza"
• "100|ADD_RESTAURANT|R1|2|burger:120,pizza:200"
• "150|ADD_RESTAURANT|R2|1|burger:110,pizza:220"
• "210|PLACE_ORDER|O2|C2|LOWEST_TOTAL_PRICE|burger"
• "220|DISPATCH_ORDER|O1"
• "205|UPDATE_MENU|R2|pizza:180"
• "230|PLACE_ORDER|O3|C3|LOWEST_TOTAL_PRICE|pizza"

• 100: add R1
• 150: add R2
• 200: place order O1 for C1 (burger,pizza) with LOWEST_TOTAL_PRICE
  • R1 total = 120 + 200 = 320, remaining capacity = 2
  • R2 total = 110 + 220 = 330, remaining capacity = 1
  • Choose R1 (lower total) and accept O1 → output ACCEPTED
• 205: update R2 pizza price to 180
• 210: place order O2 for C2 (burger) with LOWEST_TOTAL_PRICE
  • R1 burger = 120, remaining capacity = 1 (since O1 is open at R1)
  • R2 burger = 110, remaining capacity = 1
  • Choose R2 (lower total) and accept O2 → output ACCEPTED
• 220: dispatch order O1
  • Marks O1 dispatched, frees 1 slot in R1, and increments served counts for R1: burger +1, pizza +1
  • Output: DISPATCHED
• 230: place order O3 for C3 (pizza) with LOWEST_TOTAL_PRICE
  • R2 pizza = 180 but R2 capacity = 1 and it already has O2 open → cannot accept new order
  • R1 pizza = 200 and R1 has capacity available → accept at R1
  • Accept O3 → output ACCEPTED

• "ACCEPTED"
• "OK"
• "OK"
• "ACCEPTED"
• "DISPATCHED"
• "OK"
• "ACCEPTED"

Example 2: Query items served per restaurant

• "R1|burger|1"
• "R1|pizza|1"

Example 3: Show all dispatched orders for a restaurant

• "220|O1|C1|burger,pizza"