#0283

Gas Station

MediumDSA28 min20 XP

Problem

Given gas and cost arrays, return the starting index that lets you travel around the circle once, or -1 if impossible.

Why This Matters

Gas Station is a famous greedy reset problem: once a start fails, every station inside that failed segment fails too.

Function Signature

def can_complete_circuit(gas, cost):

Examples

Example 1

Inputgas = [1,2,3,4,5], cost = [3,4,5,1,2]

Output3

Starting at index 3 gives enough surplus to finish the loop.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def can_complete_circuit(gas, cost):
    """
    Input example: gas = [1,2,3,4,5], cost = [3,4,5,1,2]
    Return: 3
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return -1

def can_complete_circuit(gas, cost):
    """
    Input example: gas = [1,2,3,4,5], cost = [3,4,5,1,2]
    Return: 3
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return -1

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

Start at three

Inputgas [1,2,3,4,5], cost [3,4,5,1,2]

Expected3

Station 3 is the first viable start after failed prefixes.

Impossible total

Inputgas [2,3,4], cost [3,4,3]

Expected-1

Total gas is less than total cost.

Hidden Test Categories

start at zeroall exact matchessingle station