UVA10935 Throwing cards away I【模拟＋queue＋循环队列】

Given is an ordered deck of n cards numbered 1to n with card 1 at the top and card n at the bottom. The following operation is performed as long as there are at least two cards in the deck:

        Throw away the top card and move

        the card that is now on the top of the

        deck to the bottom of the deck.

  Your task is to find the sequence of discarded cards and the last, remaining card.

Input

Each line of input (except the last) contains a number n ≤ 50. The last line contains ‘0’ and this line should not be processed.

Output

For each number from the input produce two lines of output. The first line presents the sequence of discarded cards, the second line reports the last remaining card. No line will have leading or trailing spaces. See the sample for the expected format.

Sample Input

7

19

10

6

0

Sample Output

Discarded cards: 1, 3, 5, 7, 4, 2

Remaining card: 6

Discarded cards: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 4, 8, 12, 16, 2, 10, 18, 14

Remaining card: 6

Discarded cards: 1, 3, 5, 7, 9, 2, 6, 10, 8

Remaining card: 4

Discarded cards: 1, 3, 5, 2, 6

Remaining card: 4

问题链接：UVA10935 Throwing cards away I

问题简述：（略）

问题分析：（略）

程序说明：

　　这是一个模拟问题，直接使用队列（queue）来模拟即可。

　　然而，效率更高的做法是，自己构建一个循环队列来实现模拟。需要注意的是，那个队列的存储单元至少要比最大值大１，否则会出现下标异常。

题记：（略）

参考链接：（略）

AC的C语言程序如下：

/* UVA10935 Throwing cards away I */

#include 

#define N (50 + 1)
int cq[N], headcq, tailcq;

void pushcq(int v)
{
    cq[tailcq++] = v;
    tailcq %= N;
}

void popcq()
{
    headcq++;
    headcq %= N;
}

int frontcq()
{
    return cq[headcq];
}

int sizecq()
{
    return (tailcq + N - headcq) % N;
}

void initcq()
{
    headcq = tailcq = 0;
}

int main(void)
{
    int n, i;

    while(~scanf("%d", &n) && n) {
        initcq();

        for(i=1; i<=n; i++)
            pushcq(i);

        printf("Discarded cards:");

        int nofirst = 0;
        while(sizecq() >= 2) {
            if(nofirst)
                printf(",");
            nofirst = 1;

            printf(" %d", frontcq());

            popcq();
            pushcq(frontcq());
            popcq();
        }
        printf("\nRemaining card: %d\n", frontcq());
    }

    return 0;
}

AC的C++语言程序如下：

/* UVA10935 Throwing cards away I */

#include 
#include 

using namespace std;

int main()
{
    int n;

    while(cin >> n && n) {
        queue q;

        for(int i=1; i<=n; i++)
            q.push(i);

        cout << "Discarded cards:";

        bool nofirst = false;
        while(q.size() >= 2) {
            if(nofirst)
                cout << ",";
            nofirst = true;

            cout << " " << q.front();

            q.pop();
            q.push(q.front());
            q.pop();
        }
        cout << endl << "Remaining card: " << q.front() << endl;
    }

    return 0;
}