100302. 最小栈

难度: Easy

题目描述

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解题思路

代码实现

解决方案

java

class MinStack {

    LinkedList<Integer> data = new LinkedList<>();
    LinkedList<Integer> min = new LinkedList<>();

    /** initialize your data structure here. */
    public MinStack() {

    }

    public void push(int x) {
        data.push(x);
        if (min.isEmpty()) {
            min.push(x);
            return;
        }
        if (min.peek() < x) {
            min.push(min.peek());
        } else {
            min.push(x);
        }

    }

    public void pop() {
        data.pop();
        min.pop();
    }

    public int top() {
        if(data.size()==0){
            return 0;
        }
        return data.peek();
    }

    public int getMin() {
        if(min.size()==0){
            return 0;
        }
        return min.peek();
    }
}

/**
 * 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();
 */