Solution2.java

class Solution {
    public int maxJumps(int[] arr, int d) {
        int n = arr.length;
        Integer[] idx = new Integer[n];
        for (int i = 0; i < n; ++i) {
            idx[i] = i;
        }
        Arrays.sort(idx, (i, j) -> arr[i] - arr[j]);
        int[] f = new int[n];
        Arrays.fill(f, 1);
        int ans = 0;
        for (int i : idx) {
            for (int j = i - 1; j >= 0; --j) {
                if (i - j > d || arr[j] >= arr[i]) {
                    break;
                }
                f[i] = Math.max(f[i], 1 + f[j]);
            }
            for (int j = i + 1; j < n; ++j) {
                if (j - i > d || arr[j] >= arr[i]) {
                    break;
                }
                f[i] = Math.max(f[i], 1 + f[j]);
            }
            ans = Math.max(ans, f[i]);
        }
        return ans;
    }
}