Jump Game II

DESCRIPTION (inspired by Leetcode.com)

Imagine stepping stones across a river. You start on the first stone (index 0) and need to reach the final stone. Each stone has a number indicating the maximum distance you can leap from that position. Find the fewest number of leaps required to reach the end. You may assume a path to the end always exists.

Example 1

Input:

nums = [3, 4, 2, 1, 2, 1]

Output:

2

Explanation: From stone 0, leap to stone 1 (you could go up to 3 stones, but 1 is strategic). From stone 1, leap directly to stone 5 (4 stones forward). Total = 2 leaps.

Example 2

Input:

nums = [1, 2, 1, 1, 1]

Output:

3

Explanation: Leap 0→1, then 1→3, then 3→4. Three leaps total.