[LeetCode] Min Stack (C++)

leetcode.com/problems/min-stack/submissions/

Min Stack - LeetCode

최소값을 리턴하는 스택을 구현하는 문제였습니다.

 

/* vector */

class MinStack {
public:
    
    vector<int> v;
    
    /** initialize your data structure here. */
    MinStack() {
        
    }
    
    void push(int x) {
        v.push_back(x);
    }
    
    void pop() {
        if(!v.empty()) v.pop_back();
    }
    
    int top() {
        if(!v.empty()) return v.back();
        return NULL;
    }
    
    int getMin() {
        return *min_element(v.begin(), v.end());
    }
};

/**
 * 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();
 */

 

/* two stack */

class MinStack {
public:
    
    stack<int> s, minS;
    
    /** initialize your data structure here. */
    MinStack() {
        
    }
    
    void push(int x) {
        s.push(x);
        minS.push(minS.empty() ? x : min(minS.top(), x));
    }
    
    void pop() {
        if(!s.empty()) s.pop();
        if(!minS.empty()) minS.pop();
    }
    
    int top() {
        if(!s.empty()) return s.top();
        return NULL;
    }
    
    int getMin() {
        if(!minS.empty()) return minS.top();
        return NULL;
    }
};

/**
 * 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();
 */