第76题 Min Stack

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本文介绍了一个支持 push、pop、top 和获取最小元素的栈的设计，重点在于实现这些操作在常数时间内完成。

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

push(x) -- Push element x onto stack.
pop() -- Removes the element on top of the stack.
top() -- Get the top element.
getMin() -- Retrieve the minimum element in the stack.

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Stack Data Structure

Solution in C++:

class MinStack {
public:
    vector<int> stack;
    int min;
    
    MinStack(){
        min = INT_MAX;
    }
    
    void push(int x) {
        stack.push_back(x);
        if(x<min) min=x;
    }

    void pop() {
        int dele;
        if(stack.size()>0){
              dele = stack[stack.size()-1];
              stack.pop_back();
        }
      
        if(dele==min){
            min = INT_MAX;
            for(int i=0; i<stack.size(); i++)
                min=min<=stack[i]?min:stack[i];
            }
        }
      
        

    int top() {
        return stack[stack.size()-1];
    }

    int getMin() {
        return min;
    }
};