滑动窗口优化

CMakeLists.txt

@@ -10,9 +10,9 @@ file(GLOB_RECURSE SOURCES "src/*/*.cpp")
 add_library(${APP_LIB_NAME} ${SOURCES})
 
 include(cmake/googletest.cmake)
-option(WITH_PROFILE OFF)
-if (${WITH_PROFILE})
-    add_definitions(-DENABLE_PROFILING)
-    include(cmake/gperftools.cmake)
-endif ()
+#option(WITH_PROFILE OFF)
+#if (${WITH_PROFILE})
+#    add_definitions(-DENABLE_PROFILING)
+#    include(cmake/gperftools.cmake)
+#endif ()
 include(cmake/tests.cmake)

src/jianzhi_offer/number.cpp

@@ -3,14 +3,49 @@
 namespace yaha {
 std::vector<int> max_sliding_window(std::vector<int> &nums, int k) {
     std::vector<int> ret;
-    for (int i = 0; i < nums.size(); i++) {
-        int max_num = 0;
-        if (k + i <= nums.size()) {
-            for (int j = i; j < k + i; ++j) {
-                std::cout << nums[j] << " " << std::endl;
-                max_num = std::max(max_num, nums[j]);
-            }
-            ret.push_back(max_num);
+//    for (int i = 0; i < nums.size(); i++) {
+//        int max_num = nums[i];
+//        if (k + i <= nums.size()) {
+//            for (int j = i; j < k + i; ++j) {
+//                max_num = std::max(max_num, nums[j]);
+//            }
+//            ret.push_back(max_num);
+//        }
+//    }
+
+//    if (nums.size() == 0 || k == 0) {
+//        return ret;
+//    }
+//    std::deque<int> d;
+
+//    for (int j = 0, i = 1 - k; j < nums.size(); i++, j++) {
+//        if (i > 0 && d.front() == nums[i - 1]) {
+//            d.pop_front();
+//        }
+//        while (!d.empty() && d.back() < nums[j]) {
+//            d.pop_back();
+//        }
+//        d.push_back(nums[j]);
+//        if (i >= 0) ret.push_back(d.front());
+//    }
+
+
+    std::deque<int> d;
+    for (int i = 0; i < nums.size(); ++i) {
+        // 保证滑动窗口的数量是K，如果超过则从前面删除
+        if (i >= k && d.front() <= i - k) {
+            d.pop_front();
+        }
+
+        // 保证后面进入的数据都是这个窗口里最大的，需要遍历整个队列，维护其最大值，这个需要从后面进行队列操作
+        while (!d.empty() && nums[d.back()] <= nums[i]) {
+            d.pop_back();
+        }
+
+        d.push_back(i);
+
+        if (i >= k - 1) {
+            ret.push_back(nums[d.front()]);
         }
     }
 

tests/jianzhi_offer/min_stack_test.cpp

@@ -8,7 +8,7 @@ TEST(MinStackTest, BasicAssertions) {
     min_stack.push(0);
     min_stack.push(-3);
     ASSERT_EQ(-3, min_stack.min());
-    ASSERT_EQ(-1, min_stack.top());
     min_stack.pop();
+    ASSERT_EQ(0, min_stack.top());
     ASSERT_EQ(-2, min_stack.min());
 }

tests/jianzhi_offer/node_test.cpp

@@ -8,7 +8,10 @@ TEST(NodeTest, TestCopyRandomList) {
     head->next->next->next = new yaha::Node(4);
 
     yaha::Node *copy = head->copy_random_list(head);
-    ASSERT_EQ(copy->val, 4);
+    ASSERT_EQ(copy->val, 1);
+    ASSERT_EQ(copy->next->val, 2);
+    ASSERT_EQ(copy->next->next->val, 3);
+    ASSERT_EQ(copy->next->next->next->val, 4);
     delete copy;
     delete head;
 }

tests/jianzhi_offer/number_test.cpp

@@ -11,6 +11,22 @@ TEST(MaxSlidingWindowTest, NumbaerTest) {
 
     std::vector<int> nums2 = {1, -1};
     std::vector<int> exp2 = {1, -1};
-    res = yaha::max_sliding_window(nums, k);
-    ASSERT_EQ(exp2, res);
+    auto res2 = yaha::max_sliding_window(nums2, 1);
+    ASSERT_EQ(exp2, res2);
+
+    std::vector<int> nums3 = {7, 2, 4};
+    std::vector<int> exp3 = {7, 4};
+
+    auto res3 = yaha::max_sliding_window(nums3, 2);
+    ASSERT_EQ(exp3, res3);
+
+    std::vector<int> nums4 = {1, 3, 1, 2, 0, 5};
+    std::vector<int> exp4 = {3, 3, 2, 5};
+    auto res4 = yaha::max_sliding_window(nums4, 3);
+    ASSERT_EQ(exp4, res4);
+
+    std::vector<int> nums5 = {9, 10, 9, -7, -4, -8, 2, -6};
+    std::vector<int> exp5 = {10, 10, 9, 2};
+    auto res5 = yaha::max_sliding_window(nums5, 5);
+    ASSERT_EQ(exp5, res5);
 }