Jump Game II

Similar Problems:

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.

Your goal is to reach the last index in the minimum number of jumps.

For example:

Given array A = [2,3,1,1,4]

The minimum number of jumps to reach the last index is 2. (Jump 1 step from index 0 to 1, then 3 steps to the last index.)

Note:

You can assume that you can always reach the last index.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

## Blog link: https://code.dennyzhang.com/jump-game-ii import sys class Solution: ## Basic Ideas: greedy ## maxIndex ## preMaxIndex ## Complexity: Time O(n), Space O(n) def jump(self, nums): """ :type nums: List[int] :rtype: int """ length = len(nums) if length <= 1: return 0 maxIndex, preMaxIndex, steps = 0, 0, 0 minSteps = sys.maxsize for i in range(0, length-1): # print(i, maxIndex, preMaxIndex, length, steps, minSteps) # we can't jump anymore if i > maxIndex: break # all elements in current level has been examined if i > preMaxIndex: steps += 1 preMaxIndex = maxIndex if maxIndex < i+nums[i]: maxIndex = i+nums[i] # already found the target if maxIndex >= length-1: minSteps = min(minSteps, steps+1) return minSteps # s = Solution() # print(s.jump([7,0,9,6,9,6,1,7,9,0,1,2,9,0,3])) # 2 # print(s.jump([2,3,1,1,4])) # 2