題目描述
https://leetcode-cn.com/problems/min-stack/
思路
getMin()
—— 檢索棧中的最小元素。需要輔助棧保存最小值。其他和棧功能相同。
也可以設置變量記錄最小值。
代碼實現:
class MinStack {
public:
/** initialize your data structure here. */
MinStack() {
}
void push(int x) {
s1.push(x);
if(s2.empty() || x <= s2.top())
s2.push(x);
}
void pop() {
if(s1.top() == s2.top()) s2.pop();
s1.pop();
}
int top() {
return s1.top();
}
int getMin() {
return s2.top();
}
private:
stack<int> s1,s2;//s1棧來按順序存儲 push 進來的數據,s2用來存出現過的最小值
};
/**
* Your MinStack object will be instantiated and called as such:
* MinStack* obj = new MinStack();
* obj->push(x);
* obj->pop();
* int param_3 = obj->top();
* int param_4 = obj->getMin();
*/