LEETCODEMedium

Jump Game II

풀이일 2025 · 03 · 26기록 2 ms · 56.4 MB원문 leetcode ↗

ArrayDynamic ProgrammingGreedy

문제

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].

풀이 TypeScript

function jump(nums: number[]): number {
  let jumps = 0;
  let current_end = 0;
  let farthest = 0;

  for (let i = 0; i < nums.length - 1; i++) {
    farthest = Math.max(farthest, i + nums[i]);

    if (i === current_end) {
      jumps++;
      current_end = farthest;
      if (current_end >= nums.length - 1) break;
    }
  }
  return jumps;
}

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