2022.07.31(LC_6132_使数组中所有元素都等于零)

 方法一：优先队列

class Solution {
    public int minimumOperations(int[] nums) {
        Queue<Integer> pq = new PriorityQueue<>();
        for (int num : nums) {
            pq.offer(num);
        }
        int ans = 0;
        while (!pq.isEmpty()) {
            int min = pq.poll();
            if (min != 0) {
                List<Integer> list = new ArrayList<>();
                while (!pq.isEmpty()) {
                    list.add(pq.poll() - min);
                }
                for (int num : list) {
                    pq.offer(num);
                }
                ans++;
            }
        }
        return ans;
    }
}

方法二：哈希表 

class Solution {
    public int minimumOperations(int[] nums) {
        Set<Integer> set = new HashSet<>();
        for (int num : nums) {
            if (num != 0) {
                set.add(num);
            }
        }
        return set.size();
    }
}