Jump Game ||

class Solution:
    def jump(self, arr: List[int]) -> int:
        # If only one element, already at the end
        if len(arr) == 1 or arr[0] == 0:
            return 0

        l = 0              # left boundary of current jump range
        r = 0              # right boundary of current jump range
        jumps = 0

        # Continue until the last index is reachable
        while r < len(arr) - 1:
            farthest = r   # farthest index reachable in the next jump

            # Explore all indices in the current range [l, r]
            for i in range(l, r + 1):
                # From index i, try to extend the reach
                farthest = max(farthest, i + arr[i])

            # Move to the next jump range
            l = r + 1
            r = farthest

            # One jump completed
            jumps += 1

        return jumps