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TwoStackQueue.java
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60 lines (50 loc) · 1.62 KB
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package stackAndqueue;
import org.junit.Test;
import java.util.Stack;
/**
* Created by LXF on 2016/7/25.
*/
public class TwoStackQueue {
private Stack<Integer> stackPush = new Stack();
private Stack<Integer> stackPop = new Stack();
public TwoStackQueue() {
}
public void add(int newNum) {
this.stackPush.push(newNum);
}
public int poll() {
if (this.stackPush.isEmpty() && this.stackPop.isEmpty()) {
throw new RuntimeException("THE QUEUE IS EMPTY");
} else {
if (this.stackPop.empty()) {
while (!this.stackPush.empty()) {
this.stackPop.push(this.stackPush.pop());
}
}
return ((Integer) this.stackPop.pop()).intValue();
}
}
public int peek() {
if (this.stackPush.isEmpty() && this.stackPop.isEmpty()) {
throw new RuntimeException("THE QUEUE IS EMPTY");
} else {
if (this.stackPop.isEmpty()) {
while (!this.stackPush.isEmpty()) {
this.stackPop.push(this.stackPush.pop());
}
}
return ((Integer) this.stackPop.peek()).intValue();
}
}
@Test
public void test() {
TwoStackQueue twoStackQueue = new TwoStackQueue();
twoStackQueue.add(1);
twoStackQueue.add(6);
twoStackQueue.add(8);
System.out.println("验证peek()方法：" + twoStackQueue.peek());
twoStackQueue.poll();
System.out.println("验证poll()方法：" + twoStackQueue.poll());
System.out.println(twoStackQueue.peek());
}
}