例题3-1

开灯问题

#include<iostream.h>#include<string.h>int n, k;bool lightState[1005];int main(){memset(lightState,false,sizeof(lightState));cin>>n>>k;int i;for(i=1;i<=k;i++){int j=1;while(i*j<=n){lightState[i*j]=!lightState[i*j];j++;}}for(i=1;i<=n;i++){if(lightState[i]){cout<<i<<" ";}}cout<<endl;return 0;}

#include<stdio.h>#include<string.h>#define MAXN 1000+10int a[MAXN];int main(){int i, j, n, k, first=1;memset(a,0,sizeof(a));scanf("%d%d",&n,&k);for(i=1;i<=k;i++){for(j=1;j<=n;j++){if(j%i==0){a[j]=!a[j];}}}for(i=1;i<=n;i++){if(a[i]){if(first){first=0;}else{printf(" ");}printf("%d",i);}}printf("\n");return 0;}