Sharing an answer code of mine about FrogJmp problem of Codility lesson 3.

Lesson 3: FrogJmp

A small frog wants to get to the other side of the road. The frog is currently located at position X and wants to get to a position greater than or equal to Y. The small frog always jumps a fixed distance, D.

Count the minimal number of jumps that the small frog must perform to reach its target.

Write a function:

def solution(A, K)

that, given three integers X, Y and D, returns the minimal number of jumps from position X to a position equal to or greater than Y.

For example, given:

the function should return 3, because the frog will be positioned as follows:

  • after the first jump, at position 10 + 30 = 40
  • after the second jump, at position 10 + 30 + 30 = 70
  • after the third jump, at position 10 + 30 + 30 + 30 = 100

Assume that:

  • X, Y and D are integers within the range [1..1,000,000,000];
  • X ≤ Y.

Complexity:

  • expected worst-case time complexity is O(1);
  • expected worst-case space complexity is O(1).

Example answer code in Python 2.7

def solution(X, Y, D):
    # write your code in Python 2.7
    
    if X >= Y: # does not have to jump
        return 0;
        
    else: # have to jump
        range = Y-X
        if range % D == 0: # When the position equal to Y after jumps
            return range / D
        else: # When the position is greater than Y after jumps
            return (range / D) + 1
  • Time complexity: O(1)