gistfile1.txt

def find_local_min(A, start):
    current = A[start]
    cid = start

    while cid < len(A)-1:
        if current > A[cid+1]:
            current = A[cid+1]
            cid += 1
        else:
            break

    return cid


def find_local_max(A, start):
    current = A[start]
    cid = start

    while cid < len(A)-1:
        if current < A[cid+1]:
            current = A[cid+1]
            cid += 1
        else:
            break

    return cid


def calc(A, P, Q, R):
    return min(A[P]-A[Q], A[R] - A[Q])


def solution(A):
    c = 0
    best = -1

    P = find_local_max(A, c)

    while 1:
        Q = find_local_min(A, P)
        R = find_local_max(A, Q)


        current = calc(A, P, Q, R)

        if current > best:
            best = current

        P = R

        if len(A)-1 in [P, Q, R]:
            break

    return best