# Program to find the size of the longest sublist where car speed is constant in python

PythonServer Side ProgrammingProgramming

Suppose we have a list of numbers representing the position of a car at equally spaced intervals of time. We have to find the size of the longest sublist where the car was traveling at a constant speed.

So, if the input is like positions = [0, 4, 8, 12, 6, 4, 0], then the output will be 4, as the sublist is [0, 4, 8, 12].

To solve this, we will follow these steps −

• j := 1
• max_cnt := 0, current := 0
• distance := |positions - positions|
• while j < size of positions, do
• prev := positions[j - 1]
• if distance is same as |positions[j] - prev| , then
• current := current + 1
• otherwise,
• max_cnt := maximum of max_cnt and current
• current := 1
• distance := |positions[j] - prev|
• max_cnt := maximum of max_cnt and current
• j := j + 1
• return max_cnt + 1

Let us see the following implementation to get better understanding −

## Example

Live Demo

class Solution:
def solve(self, positions):
j = 1
max_cnt = 0
current = 0
distance = abs(positions - positions)
while j < len(positions):
prev = positions[j - 1]
if distance == abs(positions[j] - prev):
current += 1

else:
max_cnt = max(max_cnt, current)
current = 1
distance = abs(positions[j] - prev)
max_cnt = max(max_cnt, current)
j += 1
return max_cnt + 1
ob = Solution()
positions = [0, 4, 8, 12, 6, 4, 0]
print(ob.solve(positions))

## Input

[0, 4, 8, 12, 6, 4, 0]

## Output

4