题目翻译来自

Translate:USACO/frac1

 

Ordered Fractions顺序的分数

输入一个自然数N,对于一个最简分数a/b（分子和分母互质的分数）,满足1<=b<=N,0<=a/b<=1,请找出所有满足条件的分数。

描述

这有一个例子，当N=5时，所有解为：

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

给定一个自然数N，1<=n<=160，请编程按分数值递增的顺序输出所有解。

注：①0和任意自然数的最大公约数就是那个自然数②互质指最大公约数等于1的两个自然数。

格式

PROGRAM NAME: frac1

INPUT FORMAT:

(file frac1.in)

单独的一行　一个自然数N(1..160)

OUTPUT FORMAT:

(file frac1.out)

每个分数单独占一行，按照大小次序排列

SAMPLE INPUT

5

SAMPLE OUTPUT

0/11/51/41/32/51/23/52/33/44/51/1

【题解】

列举--》快排--》输出（注意重复的）

1 {
       2 ID:fuzhong2 3 PROG:frac1 4 LANG:PASCAL 5 } 6 var 7  s,f:array[1..25600] of longint; 8  z:array[1..25600] of real; 9  w:real;10   n,i,j,p:longint;11 procedure com(var x,y:longint);12    var13    i:longint;14    begin15    for i:= y div 2 +1 downto 2 do16      begin17        if (y mod i=0) and (x mod i=0) then begin y:=y div i; x:=x div i; exit; end;18      end;19      end;20 procedure qsort(l,h:longint);21 var22  i,j,tt:integer;23  t,m:real;24 begin25  i:=l; j:=h;26  m:=z[(i+j) div 2];27  repeat28  while z[i]
       
        j;38  if i
        
         l then qsort(l,j);40 end;41 begin42   assign(input,'frac1.in'); reset(input);43   assign(output,'frac1.out');rewrite(output);44   read(n);45   p:=0;46   for i:= 1 to n do47   for j:=1 to i-1 do48     begin49     inc(p);50     f[p]:=i;51     s[p]:=j;52     z[p]:=(j/i*10000)div 1;53     end;54 qsort(1,p);55 w:=-1;56 writeln('0/1');57 for i:= 1 to p do58   begin59   if z[i]=w then continue else w:=z[i];60   com(s[i],f[i]);61   writeln(s[i],'/',f[i]);62   end;63 writeln('1/1');64 close(input);65 close(output);66 end.
        
       

真心写的有点乱

 

USER: fu zhongqing [fuzhong2]TASK: frac1LANG: PASCALCompiling...Compile: OKExecuting...   Test 1: TEST OK [0.000 secs, 676 KB]   Test 2: TEST OK [0.000 secs, 676 KB]   Test 3: TEST OK [0.000 secs, 676 KB]   Test 4: TEST OK [0.000 secs, 676 KB]   Test 5: TEST OK [0.000 secs, 676 KB]   Test 6: TEST OK [0.000 secs, 676 KB]   Test 7: TEST OK [0.000 secs, 676 KB]   Test 8: TEST OK [0.000 secs, 676 KB]   Test 9: TEST OK [0.000 secs, 676 KB]   Test 10: TEST OK [0.000 secs, 676 KB]   Test 11: TEST OK [0.011 secs, 676 KB]All tests OK.

Your program ('frac1') produced all correct answers! This is your submission #2 for this problem. Congratulations!

Here are the test data inputs:

------- test 1 ----1------- test 2 ----2------- test 3 ----4------- test 4 ----7------- test 5 ----10------- test 6 ----15------- test 7 ----24------- test 8 ----50------- test 9 ----75------- test 10 ----100------- test 11 ----160

Keep up the good work!

Thanks for your submission!