趣味题

无心人

楼上，为什么不是3个5位16进制呢？

无心人

如果是3个5位16进制数字，程序如下 import List import Numeric (showHex) main = do print \$ zip [1..] [(x, y, z)|a<-[1..7], b<-[1..15]\\[a], c<-[1..15]\\[a, b], d<-[1..15]\\[a, b, c], e<-[1..15]\\[a, b, c, d], let x1 = (16^4) * a + (16^3) * b + (16^2) * c + 16 * d + e, let x = showHex x1 "", f<-[a+1..15-a]\\[b, c, d, e], g<-[1..15]\\[a, b, c, d, e, f], h<-[1..15]\\[a, b, c, d, e, f, g], i<-[1..15]\\[a, b, c, d, e, f, g, h], j<-[1..15]\\[a, b, c, d, e, f, g, h, i], let y1 = (16^4) * f + (16^3) * g + (16^2) * h + 16 * i + j, let y = showHex y1 "", let z1 = x1 + y1, z1 < 16^5, let z = showHex z1 "", (==16) \$ length \$ nub \$ z ++ x ++ y ++ "0" ]

无心人

几万个答案，被我终止了，中午没事再运行吧

〇〇

5位太大,4位已经足够测试算法速度

〇〇

P(12,4)=11880 P(15,5)=360360 差30倍 如果算上第一个和第二个数组合 1000倍 1秒变成15分钟

〇〇

2. SQL> insert into t select x,to_number(x,'fm0xxx')n from(SELECT REPLACE(SYS_CONNECT_BY_PATH(rn,','),',') x
3. 2 FROM (SELECT to_char(ROWNUM,'fmx') rn FROM DUAL CONNECT BY ROWNUM<=12)
4. 3 WHERE LEVEL=4
5. 4 CONNECT BY NOCYCLE rn<> PRIOR rn AND LEVEL<=4
6. 5 );
8. 已创建11880行。
10. 已用时间: 00: 00: 00.18
11. SQL> commit;
13. 提交完成。
15. 已用时间: 00: 00: 00.00
16. SQL> exec DBMS_STATS.GATHER_TABLE_STATS('LT','T');
18. PL/SQL 过程已成功完成。
20. 已用时间: 00: 00: 00.11
21. SQL> set autot on
22. SQL> select count(*) from(
23. 2 select a.x||'+'||b.x||'='||to_char(a.n+b.n,'fm0xxx')s
24. 3 from t a,t b --,t c
25. 4 where a.n<to_number('6000','fm0xxx')
26. 5 and a.n<b.n
27. 6 AND a.n+b.n <=to_number('cba9','fm0xxx')
28. 7 and translate('123456789abc','\$'||a.x||b.x||to_char(a.n+b.n,'fm0xxx'),'\$')is null
29. 8 );
31. COUNT(*)
32. ----------
33. 3408
35. 已用时间: 00: 01: 45.01

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〇〇

我的代码怎么变成了数学公式?

gxqcn

我的代码怎么变成了数学公式? 〇〇 发表于 2010-6-13 15:35

在美元符前加“\”即可屏蔽被误识别成TeX数学公式（我已经帮你修改好了）。

wayne

22# 无心人 你知道J语言吗 一种特别精简，同时可读性特别差的语言。 感觉Haskell的可读性也不是很好(针对外行来说的)，

〇〇

过程式语言的写法，和SQL时间差不多

2. create or replace procedure pc5
3. as
4. time_before BINARY_INTEGER;
5. time_after BINARY_INTEGER;
6. TYPE t_num IS TABLE OF PLS_INTEGER INDEX BY PLS_INTEGER ;
7. x t_num;
8. a t_num;
9. b t_num;
10. c PLS_INTEGER;
11. c1 PLS_INTEGER;
12. r PLS_INTEGER;
13. l varchar(4);
14. begin
15. c:=0;
16. time_before := DBMS_UTILITY.GET_TIME;
17. for i in to_number('1234','fm0xxx')..to_number('cba9','fm0xxx') loop
18. l:=to_char(i,'fm0xxx');
19. if substr(l,1,1)<>substr(l,2,1)and
20. substr(l,2,1)<>substr(l,3,1)and
21. substr(l,3,1)<>substr(l,4,1)and
22. substr(l,1,1)<>substr(l,3,1)and
23. substr(l,2,1)<>substr(l,4,1)and
24. substr(l,1,1)<>substr(l,4,1)and
25. instr(l,0)=0 and instr(l,'d')=0 and instr(l,'e')=0 and instr(l,'f')=0 then
26. c:=c+1;
27. if i<to_number('cba9','fm0xxx')/2 then
28. a(c):=i;
29. c1:=c;
30. end if;
31. b(c):=i;
32. x(i):=c;
33. else
34. x(i):=c;
35. end if;
36. end loop;
37. r:=0;
38. dbms_output.put_line('c='||c||'c1='||c1||a(1)||b(1));
39. FOR I IN 1 .. c1 LOOP
40. FOR J IN x(a(i))+1 .. x(to_number('cba9','fm0xxx')-a(i)) LOOP
41. --if translate('123456789abc','\$'||to_char(a(i),'fm0xxx')||to_char(b(j),'fm0xxx')||to_char(a(i)+b(j),'fm0xxx'),'\$')is null then
42. --dbms_output.put_line(to_char(a(i),'fm0xxx')||to_char(b(j),'fm0xxx')||to_char(a(i)+b(j),'fm0xxx'));
43. --NULL;
44. l:=to_char(a(i)+b(j),'fm0xxx');
45. if substr(l,1,1)<>substr(l,2,1)and
46. substr(l,2,1)<>substr(l,3,1)and
47. substr(l,3,1)<>substr(l,4,1)and
48. substr(l,1,1)<>substr(l,3,1)and
49. substr(l,2,1)<>substr(l,4,1)and
50. substr(l,1,1)<>substr(l,4,1)and
51. instr(l,0)=0 and instr(l,'d')=0 and instr(l,'e')=0 and instr(l,'f')=0
52. --length(translate('0def','\$'||l,'\$'))=4
53. and length(translate(to_char(a(i),'fm0xxx'),'\$'||l,'\$'))=4
54. and length(translate(to_char(b(j),'fm0xxx'),'\$'||l,'\$'))=4
55. and length(translate(to_char(a(i),'fm0xxx'),'\$'||to_char(b(j),'fm0xxx'),'\$'))=4 then
56. r:=r+1;
57. --dbms_output.put_line(to_char(a(i),'fm0xxx')||to_char(b(j),'fm0xxx')||to_char(a(i)+b(j),'fm0xxx'));
58. end if;
59. end loop;
60. if r>=100 then
61. exit;
62. end if;
63. end loop;
65. time_after := DBMS_UTILITY.GET_TIME;
66. DBMS_OUTPUT.PUT_LINE ('output:'||(time_after - time_before)||'rows:'||r);
67. end;
68. /

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