【九度】题目1415：不一样的循环队列

题目地址：http://ac.jobdu.com/problem.php?pid=1415
题目描述：

大家都知道数据结构里面有一个结构叫做循环队列。顾名思义，这是一个队列，并且是循环的。但是现在，淘气的囧哥给这个循环队列加上了一些规矩，其中有5条指令:

(1) Push K, 让元素K进队列。

(2) Pop，对头元素出队列。

(3) Query K，查找队列中第K个元素，注意K的合法性。

(4) Isempty，判断队列是否为空。

(5) Isfull，判断队列是否已满。

现在有N行指令，并且告诉你队列大小是M。

输入：

第一行包含两个整数N和M。1<=N,M<=100000。

接下来有N行，表示指令，指令格式见题目描述。

其中元素均在int范围。

输出：

对于指令（1），若队列已满，输出failed，否则不做输出。

对于指令（2），若队列已空，输出failed，否则不做输出。

对于指令（3），输出队列中第K个元素，若不存在，输出failed。

对于指令（4）和（5），则用yes或者no回答。

详情见样例。

样例输入：

12 2

Push 1

Push 2

Push 3

Query 2

Query 3

Isempty

Isfull

Pop

Pop

Pop

Isempty

Isfull

样例输出：

failed

2

failed

no

yes

failed

yes

no

循环队列，底层实现是数组，给出Java和C++的实现。

其实可以不用结构体，直接数组就可以。

C++ AC

#include <stdio.h>#include <string>#include <string.h>using namespace std;#define INF 10000000;const int maxm = 100002;struct QueueLoop{    int array[maxm];    int front;    int rear;};QueueLoop queue;int n,m,i;int len; bool IsEmpty(){    int front = queue.front;    int rear = queue.rear;    if (rear == front) {        return true;    }    return false;         }bool Isfull(){    int front = queue.front;    int rear = queue.rear;    if ((rear + 1) % len == front) {        return true;    }    return false;     } bool pushElement(int k){    if (Isfull()) {        return false;     }     int rear = queue.rear;     queue.array[rear] = k;     queue.rear = (rear+1) % len;     return true;}      bool popElement(){    if (IsEmpty()) {        return false;    }    int front = queue.front;    queue.front = (front+1) % len;    return true;}      void queryElement(int k){    int front = queue.front;    int rear = queue.rear;    if ( k <= 0 || rear - front < k) {        printf("failed\n");    }else{        printf("%d\n",queue.array[k + front - 1]);    }}          int main(){    while(scanf("%d%d",&n,&m) != EOF){              queue.front = 0;        queue.rear = 0;        len = m+1;        char operate[15];        for(i = 0 ; i < n; i++){            scanf("%s",operate);            if (strcmp(operate,"Push") == 0) {               int k;               scanf("%d",&k);               if (!pushElement(k)) {                   printf("failed\n");               }             }else if (strcmp(operate,"Pop") == 0) {                if (!popElement()) {                    printf("failed\n");                }             }else if (strcmp(operate,"Query") == 0) {                int k;                scanf("%d",&k);                queryElement(k);             }else if (strcmp(operate,"Isempty") == 0) {                printf("%s\n",IsEmpty() == true ? "yes" :"no");             }else {                printf("%s\n",Isfull() == true ? "yes" :"no");             }        }    }    return 0;}/**************************************************************    Problem: 1415    User: wangzhenqing    Language: C++    Result: Accepted    Time:130 ms    Memory:1412 kb****************************************************************/

Java AC 做法1

import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.StreamTokenizer;  public class Main {    /*     * 1415     */    private static QueueLoop queue;    private static int len;    public static void main(String[] args) throws Exception{        StreamTokenizer st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));        while (st.nextToken() != StreamTokenizer.TT_EOF) {            int n = (int) st.nval;            st.nextToken();            int m = (int) st.nval;            queue = new QueueLoop(m);            len = m + 1;            while (n > 0) {                n--;                st.nextToken();                String operate = st.sval;                if (operate.equals("Push")) {                    st.nextToken();                    int k = (int) st.nval;                    if (!pushElement(k)) {                        System.out.println("failed");                    }                }else if (operate.equals("Pop")) {                    if (!popElement()) {                        System.out.println("failed");                    }                }else if (operate.equals("Query")) {                    st.nextToken();                    int k = (int) st.nval;                    Integer value = queryElement(k);                    if (value == null) {                        System.out.println("failed");                    }else {                        System.out.println(value);                    }                }else if (operate.equals("Isempty")) {                    System.out.println(IsEmpty() == true ? "yes" :"no");                }else {                    System.out.println(Isfull() == true ? "yes" :"no");                }            }        }    }         private static boolean pushElement(int k){        if (Isfull()) {            return false;        }        int rear = queue.rear;        int array[] = queue.array;        array[rear] = k;        queue.array = array;        queue.rear = (rear+1) % len;        return true;    }         private static boolean popElement(){        if (IsEmpty()) {            return false;        }        int front = queue.front;                 queue.front = (front+1) % len;        return true;    }         private static Integer queryElement(int k){        int front = queue.front;        int rear = queue.rear;        int array[] = queue.array;        if ( k <= 0 || rear - front < k) {            return null;        }        return array[k + front - 1];    }              private static boolean IsEmpty(){        int front = queue.front;        int rear = queue.rear;        if (rear == front) {            return true;        }        return false;             }    private static boolean Isfull(){        int front = queue.front;        int rear = queue.rear;        if ((rear + 1) % len == front) {            return true;        }        return false;             }         public static class QueueLoop{        int array[];        int front;        int rear;        public QueueLoop(int[] array, int front, int rear) {            super();            this.array = array;            this.front = front;            this.rear = rear;        }        public QueueLoop(int size) {            array = new int[size+1];            front = 0;            rear = 0;        }        public QueueLoop() {            super();        }    }} /**************************************************************    Problem: 1415    User: wzqwsrf    Language: Java    Result: Accepted    Time:2280 ms    Memory:43496 kb****************************************************************/

Java AC 做法2

import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.StreamTokenizer;  public class Main {    /*     * 1415     */    private static int array[];    private static int front , rear;    public static void main(String[] args) throws Exception{        StreamTokenizer st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));        while (st.nextToken() != StreamTokenizer.TT_EOF) {            int n = (int) st.nval;            st.nextToken();            int m = (int) st.nval;            array = new int[m+1];            front = rear = -1;             while (n > 0) {                n--;                st.nextToken();                String operate = st.sval;                if (operate.equals("Push")) {                    st.nextToken();                    int k = (int) st.nval;                    if (rear - front == m) {                        System.out.println("failed");                    }else {                        rear ++;                        array[rear] = k;                    }                }else if (operate.equals("Pop")) {                    if (front == rear) {                        System.out.println("failed");                    }else {                        front++;                    }                }else if (operate.equals("Query")) {                    st.nextToken();                    int k = (int) st.nval;                    if ( k <= 0 || rear - front < k) {                        System.out.println("failed");                    }else {                        System.out.println(array[front + k]);                    }                }else if (operate.equals("Isempty")) {                    System.out.println(rear == front ? "yes" :"no");                }else {                    System.out.println(rear - front == m ? "yes" :"no");                }            }        }    }} /**************************************************************    Problem: 1415    User: wzqwsrf    Language: Java    Result: Accepted    Time:2190 ms    Memory:42104 kb****************************************************************/