Leetcode 55. Jump Game

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/u013596119/article/details/82459847

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.

Answer:

从右向左 greedy algorithm 找到可以跳到当前位置的左侧位置

class Solution(object):
    def canJump(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        l=len(nums)
        
        
        right=l-1
        left=right-1
        while right>0 and left>=0:
            if left+nums[left]>=right:
                right=left
                left=right-1
            else:
                left-=1
        if right<=0:
            return True
        if left<0:
            return False