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  1. Prepare
  2. Algorithms
  3. Greedy
  4. Luck Balance
  5. Discussions

Luck Balance

  • dylanvanderberg
     + 1 comment

    Why not use a heap (PriorityQueue in Java) to remove the need for the O(nlog(n)) operation of sorting the array. Adding to a heap is O(log(n)) in worst-case, but O(1) in the average case. Since that happens n times, it should be faster on average. See my implementation: 

       // Complete the luckBalance function below.
    static int luckBalance(int k, int[][] contests) {
        int numLuck = 0;
        int totalImportant = 0;
        PriorityQueue<Integer> minHeap = new PriorityQueue<Integer>(new Comparator<Integer>(){
            @Override
            public int compare(Integer obj1, Integer obj2){
                return obj1 - obj2;
            }
        });
        for(int[] contest : contests){
            numLuck += contest[0];
            if(contest[1] == 1){
                minHeap.offer(contest[0]);
                totalImportant++;
            }
        }
        for(int i = 0; i < totalImportant - k; i++){
            numLuck -= 2 * minHeap.poll();
        }
        return numLuck;
    }