题目

解答

class Solution {public int[] maxSlidingWindow(int[] nums, int k) {if (nums == null) {return null;}LinkedList<Integer> window = new LinkedList<>();List<Integer> arr = new ArrayList<>(k);int right = 0;while (right < nums.length) {int newValue = nums[right];while (!window.isEmpty() && window.peekLast() < newValue) {window.removeLast();}window.addLast(newValue);++right;if (right >= k) {arr.add(window.peekFirst());if (window.peekFirst() == nums[right - k]) {window.removeFirst();}}}int[] values = new int[arr.size()];for (int i = 0; i < arr.size(); ++i) {values[i] = arr.get(i);}return values;}
}

要点

准备的用例，如下

@Before
public void before() {t = new Solution();
}@Test
public void test001() {assertTrue(Arrays.equals(new int[] { 3, 3, 5, 5, 6, 7 },t.maxSlidingWindow(new int[] { 1, 3, -1, -3, 5, 3, 6, 7 }, 3)));
}@Test
public void test002() {assertTrue(Arrays.equals(new int[] { 1 }, t.maxSlidingWindow(new int[] { 1 }, 1)));
}@Test
public void test003() {assertTrue(Arrays.equals(new int[] { 1, -1 }, t.maxSlidingWindow(new int[] { 1, -1 }, 1)));
}@Test
public void test004() {assertTrue(Arrays.equals(new int[] { 11 }, t.maxSlidingWindow(new int[] { 9, 11 }, 2)));
}@Test
public void test005() {assertTrue(Arrays.equals(new int[] { 4 }, t.maxSlidingWindow(new int[] { 4, -2 }, 2)));
}

如下两篇文章对于滑动窗口算法的介绍通俗易懂，值得反复阅读。

• 滑动窗口算法（一）
• 滑动窗口算法基本原理与实践