题意：定义f(n,m)是第m小的数字x，使得x>n且gcd(x,n)=1
已知
求最小的n使得
k<=1e18，m<=1e2
思路：
1 #include<bits/stdc++.h> 2 using namespace std; 3 typedef long long ll; 4 typedef unsigned int uint; 5 typedef unsigned long long ull; 6 typedef pair<int,int> PII; 7 typedef pair<ll,ll> Pll; 8 typedef vector<int> VI; 9 typedef vector<PII> VII; 10 #define N 110000 11 #define M 4100000 12 #define fi first 13 #define se second 14 #define MP make_pair 15 #define pi acos(-1) 16 #define mem(a,b) memset(a,b,sizeof(a)) 17 #define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++) 18 #define per(i,a,b) for(int i=(int)a;i>=(int)b;i--) 19 #define lowbit(x) x&(-x) 20 #define Rand (rand()*(1<<16)+rand()) 21 #define id(x) ((x)<=B?(x):m-n/(x)+1) 22 #define ls p<<1 23 #define rs p<<1|1 24 25 const ll MOD=998244353,inv2=(MOD+1)/2; 26 double eps=1e-6; 27 int INF=1e9; 28 29 30 int read() 31 { 32 int v=0,f=1; 33 char c=getchar(); 34 while(c<48||57<c) {if(c=='-') f=-1; c=getchar();} 35 while(48<=c&&c<=57) v=(v<<3)+v+v+c-48,c=getchar(); 36 return v*f; 37 } 38 39 ll gcd(ll x,ll y) 40 { 41 if(y==0) return x; 42 return gcd(y,x%y); 43 } 44 45 ll f(ll n,int m) 46 { 47 //printf("n=%I64d m=%d ",n,m); 48 ll t=n; 49 while(m) 50 { 51 t++; 52 if(gcd(n,t)==1) m--; 53 } 54 //printf("t=%I64d ",t); 55 return t; 56 } 57 58 int main() 59 { 60 //freopen("1.in","r",stdin); 61 int cas=read(); 62 while(cas--) 63 { 64 ll k; 65 int m; 66 scanf("%I64d%d",&k,&m); 67 //printf("m=%d ",m); 68 ll ans=1e18; 69 for(ll t=1;t<=1000;t++) 70 { 71 ll n=k^t; 72 if(n==0) continue; 73 //printf("t=%I64d n=%I64d ",t,n); 74 if(f(n,m)-n==t) ans=min(ans,n); 75 76 } 77 if(ans==1e18) printf("-1 "); 78 else printf("%I64d ",ans); 79 } 80 81 return 0; 82 }