Stack containing min functions, including min Functions

Stack containing min functions, including min Functions
Question: To define the stack data structure, add a min function to obtain the minimum element of the stack. The time complexity of the min, push, and pop functions is O (1 ).

Analysis: in addition to the stack required by the question, a new stack is created to record the minimum value. Each time data is pushed in the original stack, it is compared with the top element of the stack in the minimum stack. If the new value is small, the new value is pushed in the minimum stack; otherwise, the top element of the stack is pushed again. pop, you just need to pop the minimum stack. in this way, the min function only needs to return the top element of the stack of the minimum stack.

 1 #include<stack> 2 #include<assert.h> 3 #include<stdio.h> 4 #include<tchar.h> 5  6 template<typename T>class  StackWithMin 7 { 8 public: 9     StackWithMin(void) {}10     virtual ~StackWithMin(void) {}11 12     T& top(void);13     const T& top(void) const;14 15     void push(const T& value);16     void pop(void);17 18     const T& min(void) const;19 20     bool empty() const;21     size_t size() const;22 23 private:24     std::stack<T> m_data;25     std::stack<T> m_min;26 };27 28 template <typename T>void StackWithMin<T>::push(const T& value)29 {30     m_data.push(value);31 32     if(m_min.size() == 0 || value < m_min.top())33         m_min.push(value);34     else35         m_min.push(m_min.top());36 }37 38 39 template <typename T>void StackWithMin<T>::pop()40 {41     assert(m_data.size() > 0 && m_min.size() > 0);42 43     m_data.pop();44     m_min.pop();45 }46 47 template<typename T>const T& StackWithMin<T>::min() const48 {49     assert(m_data.size()>0 && m_min.size() >0);50 51     return m_min.top();52 }53 54 template<typename T>T& StackWithMin<T>::top()55 {56     return m_data.top();57 }58 template <typename T>const T& StackWithMin<T>::top() const59 {60     return m_data.top();61 }62 63 template <typename T> bool StackWithMin<T>::empty() const64 {65     return m_data.empty();66 }67 68 template<typename T> size_t StackWithMin<T>::size() const69 {70     return m_data.size();71 }72 73 void Test(char* testName, const StackWithMin<int>& stack, int expected)74 {75     if(testName != NULL)76         printf("%s begins: \n", testName);77     if(stack.min() == expected)78         printf("Passed.\n");79     else80         printf("Failed.\n");81 }82 83 int main()84 {85     StackWithMin<int> stack;86     stack.push(3);87     printf("min = %d\n", stack.min());88     stack.push(4);89     printf("min = %d\n", stack.min());90     stack.push(2);91     printf("min = %d\n", stack.min());92     stack.pop();93     printf("min = %d\n", stack.min());94     95     return 0;96 }