一. 堆栈的总结

二. Easy 题目

2,1 剑指 Offer 09. 用两个栈实现队列

class CQueue {
private:
    stack<int> stack1,stack2;
public:
    CQueue() {
        while(!stack1.empty()){
           stack1.pop();
        }
        while(!stack2.empty()){
           stack2.pop();
        }
    }
    
    void appendTail(int value) {
        stack1.push(value);
    }
    
    int deleteHead() {
        int value =-1;
        if(!stack2.empty()){
            value=stack2.top();
            stack2.pop();
        }else{
            while(!stack1.empty()){
                stack2.push(stack1.top());
                stack1.pop();
            }
            if(!stack2.empty()){
            value=stack2.top();
            stack2.pop();}
        }
        return value;
    }
};

2.2 剑指 Offer 30. 包含min函数的栈

• 最小栈和最大队列的思路不一样。

class MinStack {
private:
  stack<int> stack1;
  stack<int> min_s;
public:
    /** initialize your data structure here. */
    MinStack() {
    }
    
    void push(int x) {
       stack1.push(x);
       if(min_s.empty()||x<= min_s.top() ){
           min_s.push(x);
       }
    }
    
    void pop() {
       if(min_s.top() == stack1.top()){
           min_s.pop();
       }
      stack1.pop();
    }
    
    int top() {
       return stack1.top();
    }
    
    int min() {
       return min_s.top();
    }
};