Refactor gas station circuit solution with NamedTuple

Author: cclauss

data_structures/arrays/gas_station.py

@@ -1,38 +1,46 @@
-class Solution:
-    def can_omplete_circuit(self, gas: list[int], cost: list[int]) -> int:
-        """
-        Finds the starting station index to complete the circuit,
-        or returns -1 if not possible.
-        Args:
-        gas (List[int]): List of gas available at each station.
-        cost (List[int]): List of gas costs to travel to the next station.
-        Returns:
-        int: The index of the starting station, or -1 if no solution exists.
-        Examples:
-        >>> solution = Solution()
-        >>> solution.can_omplete_circuit([1, 2, 3, 4, 5], [3, 4, 5, 1, 2])
-        3
-        >>> solution.can_omplete_circuit([2, 3, 4], [3, 4, 3])
-        -1
-        >>> solution.can_omplete_circuit([5, 1, 2, 3, 4], [4, 4, 1, 5, 1])
-        4
-        """
-        total_gas = 0
-        current_gas = 0
-        start_station = 0
+from typing import NamedTuple
 
-        for i in range(len(gas)):
-            total_gas += gas[i] - cost[i]
-            current_gas += gas[i] - cost[i]
 
-            if current_gas < 0:
-                start_station = i + 1
-                current_gas = 0
+class GasStation(NamedTuple):
+    gas: int  # Amount of gas available at this gas station
+    cost: int  # Cost of gas required to drive to the next station
 
-        if total_gas < 0:
-            return -1
-        else:
-            return start_station
+
+def can_complete_circuit(gas_stations: list[GasStation]) -> int:
+    """
+    Finds the starting station index to complete the circuit,
+    or returns -1 if not possible.
+    Args:
+      gas_stations (List[GasStation]): List of gas stations with gas and cost attributes.
+    Returns:
+      The index of the starting station, or -1 if no solution exists.
+    Examples:
+    >>> GS = GasStation
+    >>> test_stations = (
+    ...     [GS(1, 3), GS(2, 4), GS(3, 5), GS(4, 1), GS(5, 2)],
+    ...     [GS(2, 3), GS(3, 4), GS(4, 3)],
+    ...     [GS(5, 4), GS(1, 4), GS(2, 1), GS(3, 5), GS(4, 1)]
+    ... )
+    >>> can_complete_circuit(test_stations[0])
+    3
+    >>> can_complete_circuit(test_stations[1])
+    -1
+    >>> can_complete_circuit(test_stations[2])
+    4
+    """
+    total_gas = sum(station.gas - station.cost for station in gas_stations)
+    current_gas: int = 0
+    start_station = 0
+    for i, gas_station in enumerate(gas_stations):
+        needed_gas = gas_station.gas - gas_station.cost
+        total_gas += needed_gas
+        current_gas += needed_gas
+        if current_gas < 0:
+            start_station = i + 1
+            current_gas = 0
+    if total_gas < 0:
+        return -1
+    return start_station
 
 
 # Example usage with doctests