HIT OJ 1076 哈工大OJ

Ordered Fractions

	Source : Unknown
	Time limit : 3 sec		Memory limit : 32 M

Submitted : 1140, Accepted : 349

Consider the set of all reduced fractions between 0 and 1 inclusive with denominators less than or equal to N.

Here is the set when N = 5:

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 N between 1 and 160 inclusive, prints the fractions in order of increasing magnitude.

INPUT FORMAT

Several lines with a single integer N in each line. Process to the end of file.

SAMPLE INPUT

5
5

OUTPUT FORMAT

One fraction per line, sorted in order of magnitude. print a blank line after each testcase.

SAMPLE OUTPUT

0/1
1/5
1/4
1/3
2/5
1/2
3/5
2/3
3/4
4/5
1/1

0/1
1/5
1/4
1/3
2/5
1/2
3/5
2/3
3/4
4/5
1/1

直接枚举分子分母，然后排序输出即可。水题。

我的代码：

#include<stdio.h> #include<algorithm> using namespace std; struct node { int a; int b; double cur; }; int gcd(int a,int b) { if(b==0) return a; else return gcd(b,a%b); } bool cmp(node a,node b) { return a.cur<b.cur; } int main() { int n,i,j,num=0; node acm[10000]; while(scanf("%d",&n)!=EOF) { num=0; for(i=1;i<=n;i++) { for(j=0;j<=i;j++) { if(gcd(i,j)==1) { acm[num].a=j; acm[num].b=i; acm[num].cur=(j*1.0)/(i*1.0); num++; } } } sort(acm,acm+num,cmp); for(i=0;i<num;i++) printf("%d/%d\n",acm[i].a,acm[i].b); printf("\n"); } return 0; }