| 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.
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这道题简单，上代码:
1 // UVa133 The Dole Queue
2 #include<cstdio>
3 #define maxn 25
4 int n, k, m, a[maxn];
5 int go(int p, int d, int t) {
6 while(t--) {
7 do {p=(p+d+n-1)%n+1;} while(a[p] == 0);
8 }
9 return p;
10 }
11
12 int main() {
13 while(scanf("%d%d%d", &n, &k, &m) == 3 && n) {
14 for(int i = 1; i <= n; i++) a[i] = i;
15 int left = n;
16 int p1 = n, p2 = 1;
17 while(left) {
18 p1 = go(p1, 1, k);
19 p2 = go(p2, -1, m);
20 printf("%3d", p1); left--;
21 if(p2 != p1) { printf("%3d", p2); left--; }
22 a[p1] = a[p2] = 0;
23 if(left) printf(",");
24 }
25 printf("\n");
26 }
27 return 0;
28 }