STL--队列

 

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 thebottom. The following operation is performed aslong 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 discardedcards and the last, remaining card.

Input

Each line of input (except the last) contains anumber n ≤ 50. The last line contains ‘0’ andthis line should not be processed.

Output

For each number from the input produce twolines of output. The first line presents the sequenceof discarded cards, the second line reportsthe last remaining card. No line will haveleading or trailing spaces. See the sample for theexpected 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map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：

（循环队列）

/* UVA10935 Throwing cards away I */  
  
#include <stdio.h>  
  
#define N (50 + 1)  
int cq[N], headcq, tailcq;  //cq[]是循环队列
  
void pushcq(int v)  
{  
    cq[tailcq++] = v;  
    tailcq %= N;  //模除的作用是循环，
}  //入队
  
void popcq()  
{  
    headcq++;  
    headcq %= N;  
}  //出队
  
int frontcq()  
{  
    return cq[headcq];  
}  
  
int sizecq()  
{  
    return (tailcq + N - headcq) % N;  
}  
  
void initcq()  
{  
    headcq = tailcq = 0;  //初始化队列
}  
  
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;  
}