Added gas_station.py

data_structures/arrays/gas_station.py

@@ -0,0 +1,42 @@
+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
+
+ 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
+
+ if total_gas < 0:
+ return -1
+ else:
+ return start_station
+
+
+# Example usage with doctests
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()