Algorithm

https://adventofcode.com/2017/day/1

Steps

Step 1:

CQU ,front = 0 , rear = CQU.size - 1 , sum  = 0

Step 2:

if front != Rear + 1

Step 3:

if front == front + 1

sum = sum + CQU[front + 1]

Step 4:

front = front + 1

Step 5:

Repeat step 2 to 4