pylist

55. Jump Game

Given an array of non-negative integers, you are initially positioned at the first index of the array.

Each element in the array represents your maximum jump length at that position.

Determine if you are able to reach the last index.

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:

Solution

class Solution:
    def canJump(self, nums: List[int]) -> bool:
        i = -1 # location of you
        reach = 0
        
        while True:
            # update location
            i += 1
            # update reach
            reach = max(i + nums[i], reach)
            
            if i == len(nums) - 1:
                return True
            if i == reach:
                return False