package stack_and_queue;

// Find the first circular tour that visits all Petrol Pumps

public class P30 {

public int tour(int[] petrol, int[] distance) {

int start = 0;

int end = petrol.length -1 ;

int i = start;

int currPetrol = 0; int count = 0;

while(i % (petrol.length) != end) {

if(i == 0)

count++;

currPetrol += petrol[i];

if(currPetrol < distance[i]) {

if(count >= 2) return -1;

start = (i + 1) % (petrol.length);

if(start == 0) return -1;

currPetrol = 0;

end = i % petrol.length;

}

else {

currPetrol -= distance[i];

}

i++;

i %= petrol.length;

}

currPetrol += petrol[end];

if(currPetrol < distance[end])

return -1;

return start;

}

public static void main(String[] args) {

}

}