Leetcode每日随机2021/4/26

题

思

leetcode1005
每次取最小的就行，小根堆。
leetcode1655
还是费了一些时间，一开始想着是不是能直接贪心做，搞了半天发现不行的。
后来dfs暴力就过了，还是数据量比较小。

代码

leetcode1005

class Solution {
    public int largestSumAfterKNegations(int[] A, int K) {
		Queue<Integer> queue = new PriorityQueue<Integer>();
		int sum = 0;
		for (int a : A) {
			sum += a;
			queue.offer(a);
		}
		for (int i = 0; i < K; i++) {
			int head = queue.poll();
			sum -= 2 * head;
            queue.offer(-head);
		}
		return sum;
	}
}

leetcode1655

class Solution {
    public boolean canDistribute(int[] nums, int[] quantity) {
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		for (int num : nums) {
			map.put(num, map.getOrDefault(num, 0) + 1);
		}
		List<Integer> count = new ArrayList<Integer>(map.values());
		Arrays.sort(quantity);
		return dfs(count, quantity, quantity.length - 1);
	}

	private boolean dfs(List<Integer> count, int[] quantity, int idx) {
		if (idx < 0) {
			return true;
		}
		int max = 0;
		for (int i : count) {
			max = i > max ? i : max;
		}
		if (quantity[idx] > max) {
			return false;
		}
		for (int i = 0; i < count.size(); i++) {
			if (count.get(i) < quantity[idx]) {
				continue;
			}
			count.set(i, count.get(i) - quantity[idx]);
			if (dfs(count, quantity, idx - 1)) {
				return true;
			}
			count.set(i, count.get(i) + quantity[idx]);
		}
		return false;
	}
}