#include<stdio.h>\x0d #include<math.h>\x0d int main(){\x0d \x09int n,i,j,k,a[20];scanf("%d",&n);printf("Gray code n=%d\n",n);for(i=0;i<pow(2,n);i++){k=i;for(j=0;j<n;j++){a[j]=k%2;k/=2;}for(k=1;k<n;k++){if(a[k]==1&&a[k-1]==1)a[k-1]=0;else if(a[k]==1&&a[k-1]==0)a[k-1]=1;}for(k=j-1;k>=0;k--){printf("%d",a[k]);}printf("\n");}}
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