Award Link

You can find ‘Task Description’ in Codility Challenge or in ‘Review detailed assessment’ of Award Link.

Main Concept

각 stack의 coin은 한 step 좌우로 이동할 때 마다 절반으로 감소합니다.

2nd step 1st step start 1st step 2nd step
1 <- 2 <- 5 -> 2 -> 1

stack 별로 coin의 이동을 구하여 stack 별로 합산합니다.

stack 1st stack 2nd stack 3nd stack 4th stack 5th stack
original 1 2 0 4 2
1st stack 1 -> 0 -> 0 -> 0 -> 0
2nd stack 1 <- 2 -> 1 -> 0 -> 0
3rd stack 0 <- 0 <- 0 -> 0 -> 0
4th stack 0 <- 1 <- 2 <- 4 -> 2
5th stack 0 <- 0 <- 0 <- 1 <- 2
total 2 3 3 5 4

위 합산 중 최대값을 가진 stack의 coin 수가 해답이 됩니다.

Computational Complexity (Big-O)

O(N) for worst/general/best cases.