Ordered Fractions

链接

分析：遍历一下，求个gcd即可，最后按照ans排序并去重

 /*
     PROB:frac1
     ID:wanghan
     LANG:C++
 */
 #include "iostream"
 #include "cstdio"
 #include "cstring"
 #include "string"
 #include "algorithm"
 #include "vector"
 using namespace std;
 int n;
 int gcd(int a,int b){
     if(b==)  return a;
     return gcd(b,a%b);
 }
 struct Node{
     int x,y;
     double ans;
 };
 vector<Node> p;
 bool cmp(Node a,Node b){
     return a.ans<b.ans;
 }
 int main()
 {
     freopen("frac1.in","r",stdin);
     freopen("frac1.out","w",stdout);
     cin>>n;
     for(int i=;i<=n;i++){
         for(int j=min(n,i+);j<=n;j++){
             int x,y;
             x=i/gcd(i,j),y=j/gcd(i,j);
             Node t;
             t.x=x,t.y=y,t.ans=(double)x/(double)y;
             p.push_back(t);
         }
     }
     sort(p.begin(),p.end(),cmp);
     cout<<p[].x<<"/"<<p[].y<<endl;
     for(int i=;i<p.size();i++){
         if(p[i].x==p[i-].x&&(p[i].y==p[i-].y)) continue;
         cout<<p[i].x<<"/"<<p[i].y<<endl;
     }
     return ;
 }