Jump_Game.py

"""
You are given an integer array nums. You are initially positioned at the array's first index,
and each element in the array represents your maximum jump length at that position.

Return true if you can reach the last index, or false otherwise.



Example 1:

Input: nums = [2,3,1,1,4]
Output: true
Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index.
Example 2:

Input: nums = [3,2,1,0,4]
Output: false
Explanation: You will always arrive at index 3 no matter what. Its maximum jump length is 0,
which makes it impossible to reach the last index.


Constraints:

1 <= nums.length <= 104
0 <= nums[i] <= 105
"""
from typing import List


class Solution:
    def canJump(self, nums: List[int]) -> bool:
        goal_idx = len(nums) - 1

        furthest_idx_reached = 0
        for idx,step in enumerate(nums):

            if idx > furthest_idx_reached:
                return False

            furthest_idx_reached = max(furthest_idx_reached, idx + step)

            if furthest_idx_reached >= goal_idx:
                return True

        return False


if __name__ == '__main__':
    jump_game = Solution()

    assert jump_game.canJump([1,2,3])
    assert not jump_game.canJump([0,1,2,3])