新增的最少台阶数

// Java Stream API solution with detailed comments
// We aim to find the minimum number of additional rungs required so that no gap exceeds 'dist'.
import java.util.stream.IntStream;

public class LadderStream {
    public int addRungs(int[] rungs, int dist) {
        // Starting from the ground level
        int[] previousHeight = {0};

        return IntStream.of(rungs)
            .map(rung -> {
                // Calculate the number of rungs needed if the gap exceeds dist
                int needed = (rung - previousHeight[0] - 1) / dist;
                previousHeight[0] = rung; // Update previous height
                return needed;
            })
            .sum(); // Sum up the required rungs
    }
}