?pid=5175
若gcd(a,b）= a xor b=c，则b=a-c (打表发现的)
c是a的因子，，则枚举a的所有因子判断b是否满足a^b=c 93MS 1104K 893 B
;ll n;vector<ll> vl;int main(){int Case=1;while(scanf(“%I64d”,&n)!=EOF){vl.clear();printf(“Case #%d:\n”, Case++);for(ll c=1;c*c<=n;++c){if(n%c==0){ll b=n-c;if( b>0&&(n^b)==c){vl.push_back(b);}if(n/c!=c){b=n-n/c;if(b>0&&b<=n&&((n^b)==(n/c))) vl.push_back(b);}}}sort(vl.begin(),vl.end());printf(“%d\n”,vl.size());for(int i=0;i<vl.size();++i){printf(“%I64d”,vl[i]);if(i!=vl.size()-1) printf(” “);}printf(“\n”);}return 0;}
只要功夫深，铁棒磨成绣花针。
