Count Big Steps

Background

Congcong is planning a hiking trip. He has a map recording the altitudes along the trail.

Problem Description

(A variation on the sumHeights problem.) We have an array of heights, representing the altitude along a walking trail. Given start/end indexes into the array, return the number of "big" steps for a walk starting at the $start$ index and ending at the $end$ index. We'll say that step is big if it is $5$ or more up or down. The $start$ and $end$ index will both be valid indexes into the array with $start \le end$.

Input Format

The input consists of a single line.

[h_0 h_1 ... h_{N-1}] start end The first part is a list of integers enclosed in square brackets [] with elements separated by spaces, representing the array of heights. The second part consists of two integers, $start$ and $end$, representing the starting and ending indices of the walk.

Output Format

Output to standard output in the following format.

count Where count is the number of "big" steps.

Sample

[5 3 6 7 2] 2 4

1

[5 3 6 7 2] 0 1

0

[5 3 6 7 2] 0 4

1

Sample Explanation

For Sample 1: [5 3 6 7 2] 2 4 The start index is $2$, and the end index is $4$. From $heights[2]$ to $heights[3]$: $|7 - 6| = 1$, not a big step. From $heights[3]$ to $heights[4]$: $|2 - 7| = 5$, this is a big step. There is a total of $1$ big step.

Constraints

Time limit: 1s, Memory limit: 1024KiB for each test case.