救济金发放（The Dole Queue, UVa 133）

#include<stdio.h>
#define maxn 22
int n, k, m, a[maxn];
int i;

int go(int p, int d, int t) {//步长为d(顺时针走为-1),走t步
while(t--) {
do{ p = (p+d+n-1)%n+1;}//重要！
while(a[p] == 0);//为了略过以输出的0，走到下一个非0的数字
}
return p;
}
int main() {
while(scanf("%d%d%d", &n, &k, &m) == 3 && n) {
for(i = 1; i <= n; ++i)
a[i] = i;
int left = n;//还剩下的人数
int p1 = n, p2 = 1;
while(left) {
p1 = go(p1, 1, k);
p2 = go(p2, -1, m);
printf("%3d", p1);
left --;
if(p2 != p1) {
printf("%3d", p2);
left--;
}
a[p1] = a[p2] = 0;
if(left) printf(",");
}
printf("\n");
}

return 0;
}