55. Jump Game

• categories: Code, Interview Question, leetcode, Medium
• source: https://leetcode.com/problems/jump-game/
• topics: Dynamic Programming

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.

class Solution:
    def canJump(self, nums: List[int]) -> bool:
        memo = {}
 
        def jump(i):
            nonlocal memo
            if i not in memo:
                if i < 0:
                    memo[i] = False
                elif i == 0:
                    memo[i] = True
                else:
                    memo[i] = False
                    for j in range(i-1, -1, -1):
                        memo[i] = (nums[j] >= (i-j) and jump(j))
                        if memo[i]:
                            break
            return memo[i]
 
        return jump(len(nums)-1)