UVa133.The Dole Queue

题目链接：http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=69

13874119

133

The Dole Queue

Accepted

C++

0.009

2014-07-13 02:44:49

---

 The Dole Queue 

In a serious attempt to downsize (reduce) the dole queue, The New National Green Labour Rhinoceros Party has decided on the following strategy. Every day all dole applicants will be placed in a large circle, facing inwards. Someone is arbitrarily chosen as number 1, and the rest are numbered counter-clockwise up to N (who will be standing on 1's left). Starting from 1 and moving counter-clockwise, one labour official counts off k applicants, while another official starts from N and moves clockwise, counting m applicants. The two who are chosen are then sent off for retraining; if both officials pick the same person she (he) is sent off to become a politician. Each official then starts counting again at the next available person and the process continues until no-one is left. Note that the two victims (sorry, trainees) leave the ring simultaneously, so it is possible for one official to count a person already selected by the other official.

Input

Write a program that will successively read in (in that order) the three numbers (N, k and m; k, m > 0, 0 < N < 20) and determine the order in which the applicants are sent off for retraining. Each set of three numbers will be on a separate line and the end of data will be signalled by three zeroes (0 0 0).

Output

For each triplet, output a single line of numbers specifying the order in which people are chosen. Each number should be in a field of 3 characters. For pairs of numbers list the person chosen by the counter-clockwise official first. Separate successive pairs (or singletons) by commas (but there should not be a trailing comma).

Sample input

10 4 3
0 0 0

Sample output

4 8, 9 5, 3 1, 2 6, 10, 7

where represents a space.

---

解题思路：一道非常类似约瑟夫问题的题目。http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=1197
　　　　 （关于约瑟夫问题，可以翻阅《具体数学》第一章引例。）

　　　　　直接数组模拟就好，没特殊机巧。白书上标程的写法更加精炼，要多学学优化自身的代码！

 #include <iostream>
 #include <cstring>
 #include <cstdio>

 using namespace std;

 const int maxn = ;
 int n, m, k, peo[maxn];

 int solve_z(int cur_first, int step_time) {
     int ans = cur_first;
     while (step_time --) {
         ans ++;
         if (ans > n) ans = ;
         while (peo[ans] == -) {
             ans ++;
             if (ans > n) ans = ;
         }
     }
     return ans;
 }

 int solve_f(int cur_first, int step_time) {
     int ans = cur_first;
     while (step_time --) {
         ans --;
         if (ans == )  ans = n;
         while (peo[ans] == -) {
             ans --;
             if (!ans) ans = n;
         }
     }
     return ans;
 }

 int main() {
     while (cin >> n >> k >> m) {
         if (n + k + m == ) break;
         for (int i =  ;  i <= n; i ++) {
             peo[i] = i;
         }

         int left_peo = n;
         int cur1 = n, cur2 = ;
         while (left_peo != ) {
             cur1 = solve_z(cur1, k);
             //cout << cur1 << endl;
             cur2 = solve_f(cur2, m);
             //cout << cur2 << endl;
             //system("pause");
             printf("%3d", cur1); left_peo --;
             if (cur2 != cur1) {
                 printf("%3d", cur2);
                 left_peo --;
             }
             //cout << ",";
             peo[cur1] = peo[cur2] = -;
             if(left_peo) cout << ",";
         }
         cout << endl;
     }

     return ;
 }

---