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题目

• 原题连接：155. 最小栈

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1- 思路

思路

• 最小栈 ——> 借助两个栈来实现

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2- 实现

⭐155. 最小栈——题解思路

class MinStack {Stack<Integer> data;Stack<Integer> min;public MinStack() {data = new Stack<>();min = new Stack<>();}// 判断当前元素和 min 的peek大小public void push(int val) {data.push(val);if(min.isEmpty() || val<=min.peek()){min.push(val);}else{min.push(min.peek());}}public void pop() {data.pop();min.pop();}public int top() {return data.peek();}public int getMin() {return min.peek();}
}

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3- ACM 实现

public class MinStack {Stack<Integer> data;Stack<Integer> min;public MinStack(){data = new Stack<>();min = new Stack<>();}public void push(int val){data.push(val);if(min.isEmpty() || val<=min.peek()){min.push(val);}else{min.push(min.peek());}}// poppublic void pop(){data.pop();min.pop();}// top()public int top(){return data.peek();}// getMin()public int getMin(){return min.peek();}public static void main(String[] args) {Scanner scanner = new Scanner(System.in);MinStack minStack = null;while (scanner.hasNext()) {String command = scanner.next();if (command.equals("push")) {int value = scanner.nextInt();minStack.push(value);} else if (command.equals("pop")) {minStack.pop();} else if(command.equals("MinStack")) {minStack = new MinStack();}else if (command.equals("top")) {System.out.println(minStack.top());} else if (command.equals("getMin")) {System.out.println(minStack.getMin());}}scanner.close();}}

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