剑指 Offer 40. 最小的k个数

Author: geekidentity

src/main/java/com/geekidentity/leetcode/offer/sort/Offer40GetLeastNumbers.java

@@ -0,0 +1,33 @@
+package com.geekidentity.leetcode.offer.sort;
+
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+/**
+ * 排序
+ * 剑指 Offer 40. 最小的k个数
+ * https://leetcode-cn.com/problems/zui-xiao-de-kge-shu-lcof/
+ */
+public class Offer40GetLeastNumbers {
+    public int[] getLeastNumbers(int[] arr, int k) {
+        if (arr == null || arr.length == 0 || k == 0) {
+            return new int[0];
+        }
+
+        Queue<Integer> maxStack = new PriorityQueue<>((a, b) -> b - a);
+        for (int i : arr) {
+            if (maxStack.size() < k) {
+                maxStack.offer(i);
+            } else if (maxStack.peek() > i) {
+                maxStack.poll();
+                maxStack.offer(i);
+            }
+        }
+        int[] result = new int[maxStack.size()];
+        int i = 0;
+        for (Integer n : maxStack) {
+            result[i++] = n;
+        }
+        return result;
+    }
+}