Truck Tour HackerRank Solution

In this Truck Tour HackerRank solution, There is a circle. There are  petrol pumps on that circle. Petrol pumps are numbered  to  (both inclusive). You have two pieces of information corresponding to each of the petrol pump: (1) the amount of petrol that particular petrol pump will give, and (2) the distance from that petrol pump to the next petrol pump.

Initially, we have a tank of infinite capacity carrying no petrol. You can start the tour at any of the petrol pumps. Calculate the first point from where the truck will be able to complete the circle. Consider that the truck will stop at each of the petrol pumps. The truck will move one kilometer for each litre of the petrol.

Truck Tour HackerRank solution

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Problem Solution in Python

def truckTour(petrolpumps):
    tank = startingIndex = 0
   
    for i in range(len(petrolpumps)):
        tank += petrolpumps[i][0]
       
        if tank >= petrolpumps[i][1]:
            tank -= petrolpumps[i][1]
        else:
            tank = 0
            startingIndex = i + 1
   
    return startingIndex

func truckTour(petrolpumps [][]int32) int32 {
    // Write your code here
    var gas,i int32
    total := int32(len(petrolpumps))
    n := total
    for n > 0 {
        gas += petrolpumps[i][0] - petrolpumps[i][1]
        i = (i + 1) % total
        n--
        if gas < 0 {
            n = total
            gas = 0
        }
    }
    // i will loop back to viable starting index when n == 0
    return i
}

int truckTour(vector<vector<int>> petrolpumps) {
    int n = petrolpumps.size();
    for (int i = 0; i < n; i++)
    {
        int petrol = 0;
        int index = i;
        if (petrolpumps[i][0] < petrolpumps[i][1])
            continue;
        while (true)
        {
            petrol += petrolpumps[index][0];
            petrol -= petrolpumps[index][1];
            if(petrol < 0)
                break;
            index = (index + 1)%n;
            if(index == i)
                break;
        }
        if (index == i)
            return i;
    }
    return -1;
}

function truckTour(petrolpumps) {
    let petrol = 0, distance = 0, first = 0;
    for (let i=0; i<petrolpumps.length; i++){
        petrol+=petrolpumps[i][0];
        distance+=petrolpumps[i][1];
        if (petrol<distance){
            petrol=0, distance=0;
            first=i+1;
        }
    }
    return first;
}