棧和隊列沒想象中那麼難

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class Node {\n\n //數據域\n public int data;\n\n //指針域，指向下一個節點\n public Node next;\n\n public Node() {\n }\n\n public Node(int data) {\n this.data = data;\n }\n\n public Node(int data, Node next) {\n this.data = data;\n this.next = next;\n 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/**\n * 判斷該棧是否爲空\n *\n * @param stack\n */\n public static void isEmpty(Stack stack) {\n if (stack.stackTop == stack.stackBottom) {\n\n System.out.println(\"關注公衆號：Java3y---->該棧爲空\");\n } else {\n\n System.out.println(\"關注公衆號：Java3y---->該棧不爲空\");\n\n }\n\n 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rear;\n\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"從上面的設計我們可以發現：","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"rear並不指向最後一個有效的元素，在循環隊列中這樣設計是非常方便的","attrs":{}},{"type":"text","text":"！因爲這樣設計可以","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"讓我們分得清隊頭和隊尾","attrs":{}},{"type":"text","text":"(不然循環隊列不斷入隊或出隊，位置是變化很快的)","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"由於我們是循環隊列，所以","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"front","attrs":{}}],"attrs":{}},{"type":"text","text":"和","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"rear","attrs":{}}],"attrs":{}},{"type":"text","text":"值會經常變動，我們得把","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"front","attrs":{}}],"attrs":{}},{"type":"text","text":"和","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"rear","attrs":{}}],"attrs":{}},{"type":"text","text":"的值限定在一個範圍內，不然會超出隊列的長度的。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有這麼一個算法：","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"rear=（rear+1)%數組長度","attrs":{}}],"attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"比如rear的下標是2，數組的長度是6，往後面移一位是3，那麼","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"rear = （rear+1) % 6","attrs":{}}],"attrs":{}},{"type":"text","text":"，結果還是3","attrs":{}}]}]}],"attrs":{}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.2初始化隊列","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"此時隊列爲空，分配了6個長度給數組(只能裝5個實際的數字，rear指向的是無效的位置的)","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n public static void main(String[] args) {\n\n //初始化隊列\n Queue queue = new Queue();\n\n queue.front = 0;\n queue.rear = 0;\n queue.arrays = new int[6];\n\n }\n","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.3判斷隊列是否滿了","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"如果rear指針和front指針緊挨着，那麼說明隊列就滿了","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n /**\n * 判斷隊列是否滿了，front和rear指針緊挨着，就是滿了\n * @param queue\n * @return\n */\n public static boolean isFull(Queue queue) {\n if ((queue.rear + 1) % queue.arrays.length == queue.front) {\n\n System.out.println(\"關注公衆號：Java3y--->此時隊列滿了！\");\n return true;\n } else {\n System.out.println(\"關注公衆號：Java3y--->此時隊列沒滿了！\");\n return false;\n }\n }\n","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.4入隊","attrs":{}}]},{"type":"numberedlist","attrs":{"start":1,"normalizeStart":1},"content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","text":"判斷該隊列是否滿了","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","text":"入隊的值插入到隊尾中(具體的位置就是rear指針的位置【再次聲明：rear指向的是無效元素的位置】","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","text":"rear指針移動(再次指向無效的元素位置)","attrs":{}}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n /**\n * 入隊\n *\n * @param queue\n */\n public static void enQueue(Queue queue,int value) {\n\n // 不是滿的隊列才能入隊\n if (!isFull(queue)) {\n\n // 將新的元素插入到隊尾中\n queue.arrays[queue.rear] = value;\n\n // rear節點移動到新的無效元素位置上\n queue.rear = (queue.rear + 1) % queue.arrays.length;\n }\n }\n","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.5遍歷","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"只要front節點不指向rear節點，那麼就可以一直輸出","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n /**\n * 遍歷隊列\n * @param queue\n *\n */\n public static void traverseQueue(Queue queue) {\n\n // front的位置\n int i = queue.front;\n\n while (i != queue.rear) {\n\n System.out.println(\"關注公衆號：Java3y--->\" + queue.arrays[i]);\n\n //移動front\n i = (i + 1) % queue.arrays.length;\n }\n\n }\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"隊列沒滿時：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/db/db7b300461540c9ab2050f41f343353e.jpeg","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"隊列已滿了就插入不了了(驗證上面的方法是否正確)：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ef/efb83469473cfe9ca24c622217a04337.jpeg","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.6判斷該隊列是否爲空","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"只要","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"rear","attrs":{}}],"attrs":{}},{"type":"text","text":"和","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"front","attrs":{}}],"attrs":{}},{"type":"text","text":"指針指向同一個位置，那該隊列就是空的了","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n /**\n * 判斷隊列是否空，front和rear指針相等，就是空了\n * @param queue\n * @return\n */\n public static boolean isEmpty(Queue queue) {\n if (queue.rear == queue.front) {\n System.out.println(\"關注公衆號：Java3y--->此時隊列空的！\");\n return true;\n } else {\n System.out.println(\"關注公衆號：Java3y--->此時隊列非空！\");\n return false;\n }\n }\n","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3.1.7出隊","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"出隊的邏輯也非常簡單：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"numberedlist","attrs":{"start":1,"normalizeStart":1},"content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","text":"判斷該隊列是否爲null","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","text":"如果不爲null，則出隊，","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"只要front指針往後面移就是出隊了","attrs":{}},{"type":"text","text":"!","attrs":{}}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\n /**\n * 出隊\n *\n * @param queue\n */\n public static void outQueue(Queue queue) {\n\n //判斷該隊列是否爲null\n if (!isEmpty(queue)) {\n\n //不爲空纔出隊\n int value = queue.arrays[queue.front];\n System.out.println(\"關注公衆號：Java3y--->出隊的元素是：\" + value);\n\n // front指針往後面移\n queue.front = (queue.front + 1) % queue.arrays.length;\n\n }\n\n }\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ea/ea2facd2713bc36e9eddfa47febdc1ba.jpeg","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"四、總結","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"數據結構的棧和隊列的應用非常非常的多，這裏也只是最簡單的入門，理解起來也不困難。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"棧：先進後出","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"隊列：先進先出","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"關於數據結構這方面我就到暫時到這裏爲止了，都簡單的入個門，以後遇到更加複雜的再繼續開新的文章來寫～畢竟現在水平不夠，也無法理解更深層次的東西～數據結構這東西是必備的，等到研究集合的時候還會來回顧它，或者遇到新的、複雜的也會繼續學習....","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"想要更加深入數據結構的同學就得去翻閱相關的書籍咯～這僅僅是冰山一角","attrs":{}}]}]}