75 lines
1.9 KiB
Java
75 lines
1.9 KiB
Java
//用两个栈实现一个队列。队列的声明如下，请实现它的两个函数 appendTail 和 deleteHead ，分别完成在队列尾部插入整数和在队列头部删除整数的
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//功能。(若队列中没有元素，deleteHead 操作返回 -1 )
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//
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//
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//
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// 示例 1：
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//
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// 输入：
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//["CQueue","appendTail","deleteHead","deleteHead"]
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//[[],[3],[],[]]
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//输出：[null,null,3,-1]
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//
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//
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// 示例 2：
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//
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// 输入：
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//["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"]
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//[[],[],[5],[2],[],[]]
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//输出：[null,-1,null,null,5,2]
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//
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//
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// 提示：
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//
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//
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// 1 <= values <= 10000
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// 最多会对 appendTail、deleteHead 进行 10000 次调用
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//
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// Related Topics 栈 设计
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// 👍 212 👎 0
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package leetcode.editor.cn;
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import java.util.Stack;
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//剑指 Offer 09:用两个栈实现队列
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public class YongLiangGeZhanShiXianDuiLieLcof {
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public static void main(String[] args) {
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//测试代码
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// Solution solution = new YongLiangGeZhanShiXianDuiLieLcof().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class CQueue {
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Stack<Integer> stack1;
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Stack<Integer> stack2;
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public CQueue() {
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stack1 = new Stack<>();
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stack2 = new Stack<>();
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}
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public void appendTail(int value) {
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stack1.push(value);
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}
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public int deleteHead() {
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if (stack2.isEmpty()) {
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while (!stack1.isEmpty()) {
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stack2.push(stack1.pop());
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}
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}
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return stack2.isEmpty() ? -1 : stack2.pop();
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}
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}
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/**
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* Your CQueue object will be instantiated and called as such:
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* CQueue obj = new CQueue();
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* obj.appendTail(value);
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* int param_2 = obj.deleteHead();
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*/
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//leetcode submit region end(Prohibit modification and deletion)
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} |