PUZZLEUP 2017

newkid

用1出现个数模拟顺时针：
SELECT COUNT(*)
  FROM ( SELECT NVL(LENGTH(REPLACE(SYS_CONNECT_BY_PATH(c,','),',')),0) n
           FROM (SELECT '1' c FROM DUAL UNION ALL SELECT '' FROM DUAL)
         WHERE LEVEL=12
         CONNECT BY LEVEL<=12
       )
WHERE MOD(N*60-(12-n)*60,360)=0;


  COUNT(*)
----------
     1366
     

POWER(2,12)
-----------
     4096

用组合公式：
WITH cc(m,n,lvl) as (
select 1,1,0 from dual
union all
select m*(12-lvl),n*(lvl+1),lvl+1 from cc where lvl<12
)
select sum(m/n) from cc where mod(lvl,3)=0;


  SUM(M/N)
----------
      1366

solomon_007

newkid 发表于 2017-12-25 10:45
用1出现个数模拟顺时针：
SELECT COUNT(*)
  FROM ( SELECT NVL(LENGTH(REPLACE(SYS_CONNECT_BY_PATH(c,' ...

这还要加个约分啦