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45. Jump Game II

Array Dynamic Programming Greedy

Problem - Jump Game II

Medium

You are given a 0-indexed array of integers nums of length n. You are initially positioned at index 0.

Each element nums[i] represents the maximum length of a forward jump from index i. In other words, if you are at index i, you can jump to any index (i + j) where:

  • 0 <= j <= nums[i] and
  • i + j < n

Return the minimum number of jumps to reach index n - 1. The test cases are generated such that you can reach index n - 1.

 

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
  • It's guaranteed that you can reach nums[n - 1].

Solutions

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class Solution:
    def jump(self, nums: List[int]) -> int:
        result = highest = last = 0
        for i, val in enumerate(nums[:-1]):
            highest = max(highest, i + val)
            if last == i:
                result += 1
                last = highest
        return result

Submission Stats:

  • Runtime: 3 ms (96.89%)
  • Memory: 18.7 MB (56.88%)