题解 | #最小的K个数#

package suanfa.array;

import java.util.*;

/**

• 获取最小的k个数字

• /
  public class GetLeastNumbers {

  public static void main(String[] args) {

    int[] nums = new int[]{3, 2, 1};
    List<Integer> result = getLeastNumbersBySort(nums, 2);

  }

  /**

  • 通过堆实现

  • @param nums

  • @param k

  • @return

  • /
    public static List<integer> getLeastNumbers(int[] nums, int k) {</integer>

    PriorityQueue<integer> queue = new PriorityQueue<>(new Comparator<integer>() {</integer></integer>

      @Override
      public int compare(Integer o1, Integer o2) {
          return o2 - o1;
      }

    });

    for (int num : nums) {

      if (queue.size() < k) {
          queue.offer(num);
      } else {
          if (queue.peek() > num) {
              queue.poll();
              queue.offer(num);
          }
      }

    }

    List<integer> list = new ArrayList<>();</integer>

    while (queue.size() > 0) {

      list.add(queue.poll());

    }
    return list;
    }

    /**

  • 对数组升序排序

  • @param nums

  • @param k

  • @return

  • /
    public static List<integer> getLeastNumbersBySort(int[] nums, int k) {</integer>

    Arrays.sort(nums);
    List<integer> result = new ArrayList<>();</integer>

    for (int i = 0; i < k; i++) {

      result.add(nums[i]);

    }
    return result;
    }
    }