/* 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 tex2html_wrap_inline34 4 tex2html_wrap_inline34 8, tex2html_wrap_inline34 9 tex2html_wrap_inline34 5, tex2html_wrap_inline34 3 tex2html_wrap_inline34 1, tex2html_wrap_inline34 2 tex2html_wrap_inline34 6, tex2html_wrap_inline50 10, tex2html_wrap_inline34 7 where tex2html_wrap_inline50 represents a space.*/ #include<stdio.h> #include<math.h> #include<string.h> int main() { int n,k,m,CNT=0,i0=0,j0=0,a,b,i,j,flaga,flagb,cnta=0,cntb=0,first=1; int ppel[20]; while(scanf("%d%d%d",&n,&k,&m)==3&&n) { CNT=0; memset(ppel,0,sizeof(ppel)); for(i=0;i<n;i++){ppel[i]=i+1;} first=1;j0=i0=0; while(1) { a=b=-1; flaga=flagb=1; cnta=cntb=0; for(i=i0;;i++) { if(ppel[i%n]!=0) cnta++; if(cnta%k==0&&cnta!=0) { a=ppel[i%n]; flaga=0; } if(!flaga) {i0=i+1;break;} } for(j=j0;;j++) { if(j>n-1) j=0; if(ppel[(n-1-j)%n]!=0) cntb++; if(cntb%m==0&&cntb!=0) { b=ppel[(n-1-j)%20]; flagb=0; } if(!flagb){j0=j+1;break;} } if(first) { if(a==b) {printf("%3d",a);CNT++;} else {printf("%3d%3d",a,b);CNT+=2;} first=0; } else { if(a==b) {printf(",%3d",a);CNT++;} else {printf(",%3d%3d",a,b);CNT+=2;} } ppel[i%n]=0; ppel[(n-1-j)%20]=0; if(CNT==n) break; } putchar('\n'); } // putchar('\n'); return 0; } // 一开始老wa,不知道为什么,后来用正确的程序在cmd与它对比才发现多输出了末尾的一行空行。 而且我的方法比较不简洁,也没把顺时针逆时针统一成一个式子。 入门经典标准答案: #include<stdio.h> #define maxn 25 int n,k,m; int a[25]; int go(int p,int d,int t) { while(t--){ do{p=(p+d+n-1)%n+1; } while(a[p]==0); } return p; } int main() { while(scanf("%d%d%d",&n,&k,&m)==3&&n) { for(int i=1;i<=n;i++) a[i]=i; int left=n; 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; } /*有三点值得学习: 1.用了外部函数引用方便,使代码简洁。 2.用了一个式子把顺时针逆时针统一了起来。 3.用了数组a[1],a[2]...到a[n]来代替环,时后面的逻辑更易懂,而不像我写的用a[0],..,a[n-1]代替环。 4.用 数组a[1],a[2]...到a[n]来代替环的余数除法有小技巧。 为了体现3,4两点的优点和区别我又改写成下面的代码,同样ac: */ #include<stdio.h> #define maxn 25 int n,k,m; int a[25]; int go(int p,int d,int t) { while(t--){ do{p=(p+d+n)%n; } while(a[p]==0); } return p; } int main() { while(scanf("%d%d%d",&n,&k,&m)==3&&n) { for(int i=0;i<n;i++) a[i]=i+1; // for(int i=0;i<10;i++) printf("%d",a[i]); int left=n; int p1=n-1,p2=0; while(left) { p1=go(p1,1,k); p2=go(p2,-1,m); printf("%3d",a[p1]);left--; if(p2!=p1){printf("%3d",a[p2]);left--; } a[p1]=a[p2]=0; if(left) printf(","); } printf("\n"); } return 0; } //把入门经典 改成了 用a[0],..,a[n-1]代替环。统一顺逆的式子也需要改变。从而相形见绌、