C容器适配器应用指南容器适配器是STL提供的特殊容器接口它们基于底层容器实现特定的数据结构语义。标准库提供了stack、queue和priority_queue三种容器适配器。std::stack提供后进先出的栈语义默认使用deque作为底层容器。#include#include#include#includevoid basic_stack_usage() {std::stack s;s.push(10);s.push(20);s.push(30);std::cout Stack size: s.size() \n;std::cout Top element: s.top() \n;while (!s.empty()) {std::cout s.top() ;s.pop();}std::cout \n;}templateclass Stack {Container container_;public:void push(const T value) {container_.push_back(value);}void push(T value) {container_.push_back(std::move(value));}void pop() {if (!empty()) {container_.pop_back();}}T top() {return container_.back();}const T top() const {return container_.back();}bool empty() const {return container_.empty();}size_t size() const {return container_.size();}};void custom_stack_example() {Stack vec_stack;vec_stack.push(1);vec_stack.push(2);vec_stack.push(3);while (!vec_stack.empty()) {std::cout vec_stack.top() ;vec_stack.pop();}std::cout \n;}std::queue提供先进先出的队列语义。#includevoid basic_queue_usage() {std::queue q;q.push(first);q.push(second);q.push(third);std::cout Queue size: q.size() \n;std::cout Front: q.front() \n;std::cout Back: q.back() \n;while (!q.empty()) {std::cout q.front() ;q.pop();}std::cout \n;}templateclass Queue {Container container_;public:void push(const T value) {container_.push_back(value);}void push(T value) {container_.push_back(std::move(value));}void pop() {if (!empty()) {container_.pop_front();}}T front() {return container_.front();}const T front() const {return container_.front();}T back() {return container_.back();}const T back() const {return container_.back();}bool empty() const {return container_.empty();}size_t size() const {return container_.size();}};std::priority_queue实现优先队列默认是最大堆。void priority_queue_basic() {std::priority_queue pq;pq.push(30);pq.push(10);pq.push(50);pq.push(20);std::cout Priority queue (max heap):\n;while (!pq.empty()) {std::cout pq.top() ;pq.pop();}std::cout \n;std::priority_queue, std::greater min_pq;min_pq.push(30);min_pq.push(10);min_pq.push(50);min_pq.push(20);std::cout Priority queue (min heap):\n;while (!min_pq.empty()) {std::cout min_pq.top() ;min_pq.pop();}std::cout \n;}template,typename Compare std::lessclass PriorityQueue {Container container_;Compare comp_;void heapify_up(size_t index) {while (index 0) {size_t parent (index - 1) / 2;if (!comp_(container_[parent], container_[index])) {break;}std::swap(container_[index], container_[parent]);index parent;}}void heapify_down(size_t index) {size_t size container_.size();while (true) {size_t largest index;size_t left 2 * index 1;size_t right 2 * index 2;if (left size comp_(container_[largest], container_[left])) {largest left;}if (right size comp_(container_[largest], container_[right])) {largest right;}if (largest index) break;std::swap(container_[index], container_[largest]);index largest;}}public:void push(const T value) {container_.push_back(value);heapify_up(container_.size() - 1);}void pop() {if (empty()) return;container_[0] container_.back();container_.pop_back();if (!empty()) {heapify_down(0);}}const T top() const {return container_[0];}bool empty() const {return container_.empty();}size_t size() const {return container_.size();}};void custom_priority_queue_example() {PriorityQueue pq;pq.push(30);pq.push(10);pq.push(50);pq.push(20);while (!pq.empty()) {std::cout pq.top() ;pq.pop();}std::cout \n;}容器适配器可以用于实现各种算法和数据结构。class ExpressionEvaluator {std::stack operands_;std::stack operators_;int precedence(char op) {if (op || op -) return 1;if (op * || op /) return 2;return 0;}int apply_operator(int a, int b, char op) {switch (op) {case : return a b;case -: return a - b;case *: return a * b;case /: return a / b;}return 0;}public:int evaluate(const std::string expr) {for (size_t i 0; i expr.length(); i) {if (isspace(expr[i])) continue;if (isdigit(expr[i])) {int num 0;while (i expr.length() isdigit(expr[i])) {num num * 10 (expr[i] - 0);i;}--i;operands_.push(num);} else if (expr[i] () {operators_.push(expr[i]);} else if (expr[i] )) {while (!operators_.empty() operators_.top() ! () {int b operands_.top(); operands_.pop();int a operands_.top(); operands_.pop();char op operators_.top(); operators_.pop();operands_.push(apply_operator(a, b, op));}if (!operators_.empty()) operators_.pop();} else {while (!operators_.empty() operators_.top() ! ( precedence(operators_.top()) precedence(expr[i])) {int b operands_.top(); operands_.pop();int a operands_.top(); operands_.pop();char op operators_.top(); operators_.pop();operands_.push(apply_operator(a, b, op));}operators_.push(expr[i]);}}while (!operators_.empty()) {int b operands_.top(); operands_.pop();int a operands_.top(); operands_.pop();char op operators_.top(); operators_.pop();operands_.push(apply_operator(a, b, op));}return operands_.top();}};void expression_evaluation_example() {ExpressionEvaluator eval;std::cout 3 5 * 2 eval.evaluate(3 5 * 2) \n;std::cout (3 5) * 2 eval.evaluate((3 5) * 2) \n;}优先队列可以实现任务调度系统。#include#includestruct Task {int priority;std::string name;std::function action;bool operator(const Task other) const {return priority other.priority;}};class TaskScheduler {std::priority_queue tasks_;public:void add_task(int priority, const std::string name, std::function action) {tasks_.push({priority, name, action});}void run_all() {while (!tasks_.empty()) {Task task tasks_.top();tasks_.pop();std::cout Executing task: task.name (priority: task.priority )\n;task.action();}}};void task_scheduler_example() {TaskScheduler scheduler;scheduler.add_task(1, Low priority, []() {std::cout Low priority task executed\n;});scheduler.add_task(5, High priority, []() {std::cout High priority task executed\n;});scheduler.add_task(3, Medium priority, []() {std::cout Medium priority task executed\n;});scheduler.run_all();}双端队列可以实现滑动窗口算法。#includestd::vector max_sliding_window(const std::vector nums, int k) {std::vector result;std::deque dq;for (int i 0; i nums.size(); i) {while (!dq.empty() dq.front() i - k 1) {dq.pop_front();}while (!dq.empty() nums[dq.back()] nums[i]) {dq.pop_back();}dq.push_back(i);if (i k - 1) {result.push_back(nums[dq.front()]);}}return result;}void sliding_window_example() {std::vector nums {1, 3, -1, -3, 5, 3, 6, 7};int k 3;auto result max_sliding_window(nums, k);std::cout Sliding window maximum:\n;for (int val : result) {std::cout val ;}std::cout \n;}容器适配器提供了简洁的接口来实现常见的数据结构是算法实现的重要工具。