[leetcode]55. Jump Game

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: [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: [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.

 

DFS + memorization 으로 풀었더니 Time limit exceeded 에러가 발생해서

Discussion참고한 Solution

class Solution(object):
    def canJump(self, nums) :
        last = len(nums) - 1
        for i in range(len(nums)-1, -1, -1):
            if i + nums[i] >= last:
                last = i
        return nums[0] >= last