my solution for problem 1701

Author: jeremymanning

problems/1701/jeremymanning.md

@@ -1,11 +1,48 @@
 # [Problem 1701: Average Waiting Time](https://leetcode.com/problems/average-waiting-time/description/?envType=daily-question)
 
 ## Initial thoughts (stream-of-consciousness)
+- Given the length of the customer list, I think we'll need to find an $O(n)$ solution
+- Things to track:
+    - Total wait time so far
+    - Number of customers (this is just `len(customers)`, so we don't actually need to "track" it per se...but still)
+    - Current time that the chef is occupied until
+- Any special cases?  🤔...
+    - What if all of the arrival times are the same?  --> Then the average wait time is just `sum([c[1] for c in customers]) / len(customers)`
+    - Arrival times are already sorted, so no need to rearrange the list...
 
 ## Refining the problem, round 2 thoughts
+- Let's start with `totalWait = 0` and `chefBusyUntil = 0`
+- With each new customer (`[x, y]`):
+    - If `x < chefBusyUntil`:
+        - `totalWait += chefBusyUntil - x`  # wait until the chef is done with the current workload
+    - Else:
+        - `chefBusyUntil = x`  # need to wait until the next customer arrives to start on their request
+    - `totalWait += y
+    - `chefBusyUntil += y`
+- Then return `totalWait / len(customers)`
 
 ## Attempted solution(s)
 ```python
-class Solution:  # paste your code here!
-    ...
+class Solution:
+    def averageWaitingTime(self, customers: List[List[int]]) -> float:
+        totalWait = 0
+        chefBusyUntil = 0
+        
+        for x, y in customers:
+            if x < chefBusyUntil:
+                totalWait += chefBusyUntil - x
+            else:
+                chefBusyUntil = x
+            totalWait += y
+            chefBusyUntil += y
+
+        return totalWait / len(customers)
 ```
+- given test cases pass
+- `customers = [[5,2],[5,4],[10,3],[20,1],[21,10000],[21, 5]]`: pass
+- `customers = [[1, 1000]]`: pass
+- Ok, this seems fine...submitting...
+
+![Screenshot 2024-07-08 at 10 43 28 PM](https://github.com/ContextLab/leetcode-solutions/assets/9030494/d5bcb9a8-1e6d-4867-9158-2a7d68f2b796)
+
+solved!