O(n) time and O(1) space using Greedy Approach.

Author: 149ps

55. Jump Game/55. Jump Game.py

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+"""
+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.
+"""
+class Solution:
+    def canJump(self, nums: List[int]) -> bool:
+        lastIndex = len(nums) - 1
+        for i in range(len(nums)-1,-1,-1):
+            if i + nums[i] >= lastIndex:
+                lastIndex = i
+        return lastIndex == 0