单点时限: 2.0 sec
内存限制: 256 MB
Consider the set of all reduced fractions between 0 and 1 inclusive with denominators less than or equal to .
Here is the set when :
0/1 1/5 1/4 1/3 2/5 1/2 3/5 2/3 3/4 4/5 1/1
Write a program that, given an integer between and inclusive, prints the fractions in order of increasing magnitude.
输入格式
One line with a single integer .
输出格式
One fraction per line, sorted in order of magnitude.
样例
input
5
output
0/1
1/5
1/4
1/3
2/5
1/2
3/5
2/3
3/4
4/5
1/1
/*
思路：sort+set
*/
#include<iostream>
#include<algorithm>
#include<set>
#define Pair pair<int,int>
using namespace std;
struct g {
int x,y;
friend bool operator <(g a,g b) {
return a.x*b.y<a.y*b.x;
}
};
int main() {
int n;
cin>>n;
g G[n*n];
int index=0;
set<g>s;
for(int i = 1; i <= n; i++) {
for(int j = 1; j < i; j++) {
g m;
int gcd=__gcd(i,j);
m.x=j/gcd;
m.y=i/gcd;
s.insert(m);
}
}
cout<<"0/1"<<endl;
for(auto it=s.begin();it!=s.end(); it++)
cout<<(*it).x<<"/"<<(*it).y<<endl;
cout<<"1/1";
return 0;
}