Minimum Difficulty of a Job Schedule - Company-specific OAs / Amazon OA

Problems
1

https://algo.monster/problems/min_job_difficulty

2

Solution including Memoization:

public int minDifficulty(int[] jobDifficulty, int d) {
        int n = jobDifficulty.length;
        Map<Map.Entry<Integer, Integer>, Integer> memo = new HashMap<>();
        
        if (n < d || n > 300)
            return -1;
        
        if (n == d) {
            int sum = 0;
            for (int i = 0; i < n; i++) {
                sum += jobDifficulty[i];
            }
            return sum;
        }
        
        return dfs(jobDifficulty, 0, d, memo);
    }
    
    private int dfs(int[] jobDifficulty, int start, int d, Map<Map.Entry<Integer, Integer>, Integer> memo) {
        if (d == 1) {
            int max = 0;
            
            for (int i = start; i < jobDifficulty.length; i++) {
                max = Math.max(max, jobDifficulty[i]);
            }
            return max;
        }
        
        Map.Entry<Integer, Integer> key = Map.entry(d, start);
        if(memo.containsKey(key)) {
            return memo.get(key);
        }
        
        int maxDifficulty = 0;
        int minDifficultyOfSchedule = Integer.MAX_VALUE;
        for (int i = start; i < jobDifficulty.length - (d - 1); i++) {
            maxDifficulty = Math.max(maxDifficulty, jobDifficulty[i]);
            minDifficultyOfSchedule = Math.min(minDifficultyOfSchedule, 
                                               maxDifficulty + dfs(jobDifficulty, i + 1, d - 1, memo));
        }
        
        memo.put(key, minDifficultyOfSchedule);
        
        return minDifficultyOfSchedule;
    }
3

@mod I am getting lot of 404’s when clicking some of the links. For e.g. Clicking Next on this page resulting on 404. Can you fix it please ?