題目

Given an array of non-negative integers nums, 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.

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

Example 1:

Input: nums = [2,3,1,1,4]
Output: 2
Explanation: 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.

Example 2:

Input: nums = [2,3,0,1,4]
Output: 2

Constraints:

• 1 <= nums.length <= 104
• 0 <= nums[i] <= 1000

思路

貪婪演算法，題意是要求演算法最小步數，那麼就算出每一步能夠跨出的最長路徑，從而得出結果。

程式碼

python版本：

class Solution:
    def jump(self, nums: List[int]) -> int:
        l, r = 0, 0
        cnt = 0
        while r < len(nums)-1:
            l, r = r, max(i+nums[i] for i in range(l, r+1))
            cnt += 1
        return cnt