GetMin功能的栈

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我是靠谱客的博主矮小黑米，这篇文章主要介绍GetMin功能的栈，现在分享给大家，希望可以做个参考。

设计一个特殊的栈，在实现栈的基本功能的基础上，再实现返回栈中最小元素的操作

学习算法和数据结构中，买了本书，把书上的题目练习一下

本题难度：士

要求pop、push、getMin操作的时间复杂度为O（1）

代码如下

复制代码

package stackgame;
import java.util.Stack;
public class Stack1 {
private Stack<Integer> stackData;
private Stack<Integer> stackMin;
public Stack1() {
this.stackData=new Stack<Integer>();
this.stackMin=new Stack<Integer>();
}
public void push(int newNum) {
if(this.stackMin.isEmpty())
this.stackMin.push(newNum);
else if(newNum<=this.getMin())
this.stackMin.push(newNum);
this.stackData.push(newNum);
}
public int pop() {
if(this.stackData.isEmpty()) {
throw new RuntimeException("Your stack is Empty.");
}
int value=this.stackData.pop();
if (value == getMin()) {
stackMin.pop();
}
return value;
}
public int getMin() {
if(this.stackMin.isEmpty()) {
throw new RuntimeException("Your stack is Empty.");
}
return this.stackMin.peek();
}
public static void main(String[] args) {
Stack1 sc=new Stack1();
sc.push(5);
sc.push(3);
sc.push(2);
sc.push(4);
sc.push(8);
System.out.println(sc.getMin());
System.out.print(sc.stackMin.pop()+" ");
System.out.print(sc.stackMin.pop()+" ");
System.out.println(sc.stackMin.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
}
}

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package stackgame;
import java.util.Stack;
public class Stack1 {
private Stack<Integer> stackData;
private Stack<Integer> stackMin;
public Stack1() {
this.stackData=new Stack<Integer>();
this.stackMin=new Stack<Integer>();
}
public void push(int newNum) {
if(this.stackMin.isEmpty())
this.stackMin.push(newNum);
else if(newNum<=this.getMin())
this.stackMin.push(newNum);
this.stackData.push(newNum);
}
public int pop() {
if(this.stackData.isEmpty()) {
throw new RuntimeException("Your stack is Empty.");
}
int value=this.stackData.pop();
if (value == getMin()) {
stackMin.pop();
}
return value;
}
public int getMin() {
if(this.stackMin.isEmpty()) {
throw new RuntimeException("Your stack is Empty.");
}
return this.stackMin.peek();
}
public static void main(String[] args) {
Stack1 sc=new Stack1();
sc.push(5);
sc.push(3);
sc.push(2);
sc.push(4);
sc.push(8);
System.out.println(sc.getMin());
System.out.print(sc.stackMin.pop()+" ");
System.out.print(sc.stackMin.pop()+" ");
System.out.println(sc.stackMin.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
System.out.print(sc.stackData.pop()+" ");
}
}