class MyQueue {
private Stack<Integer> stackPush;
private Stack<Integer> stackPop;
public MyQueue() {
stackPush = new Stack<Integer>();
stackPop = new Stack<Integer>();
}
public void push(int x) {
stackPush.push(x);
}
public int pop() {
if (stackPush.isEmpty() && stackPop.isEmpty()) {
throw new RuntimeException("隊(duì)列為空");
} else if (stackPop.isEmpty()) {
while (!stackPush.isEmpty()) {
stackPop.push(stackPush.pop());
}
}
return stackPop.pop();
}
public int peek() {
if (stackPush.isEmpty() && stackPop.isEmpty()) {
throw new RuntimeException("隊(duì)列為空");
} else if (stackPop.isEmpty()) {
while (!stackPush.isEmpty()) {
stackPop.push(stackPush.pop());
}
}
return stackPop.peek();
}
public boolean empty() {
return stackPush.isEmpty() && stackPop.isEmpty();
}
}
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