Add Minimum Number of Rungs — LeetCode 1936 Python Solution

The problem

You are given a strictly increasing integer array rungs that represents the height of rungs on a ladder. You are currently on the floor at height 0, and you want to reach the last rung.

Example

Input

rungs = [1,3,5,10], dist = 2

Output

2

Explanation

You currently cannot reach the last rung.

Python solution

class Solution:
    def addRungs(self, rungs: List[int], dist: int) -> int:
        rungs = [0] + rungs
        return sum((b - a - 1) // dist for a, b in pairwise(rungs))

Complexity

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 1936. Add Minimum Number of Rungs is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Greedy.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

Related problems