LintCode-剑指Offer-(12)带最小值操作的栈

class MinStack {public:    MinStack() {        // do initialization if necessary    }    stack<int> s;    stack<int> minstack;    int minnum;    void push(int number) {        // write your code here        if(s.size()==0)            minnum=number;        else if(minnum>number)            minnum=number;        minstack.push(minnum);        s.push(number);    }    int pop() {        int tmp=s.top();        s.pop();        minstack.pop();        if(minstack.size()!=0)            minnum=minstack.top();        return tmp;    }    int min() {        return minnum;        // write your code here    }};