x
No Plagiarism!tGp1iUK8L9JC7Lt5EB6xposted on PENANA 「庭院深深深幾許,三深不能排一起」有兩種解法。8964 copyright protection544PENANAsc7a4G6yW5 維尼
548Please respect copyright.PENANAHxxc93yB21
8964 copyright protection544PENANAepoIYKpGa3 維尼
一、算「全部排列方式」再扣掉「深深深一起」的組合數8964 copyright protection544PENANAaVnrIqJ3Z9 維尼
*全部:有七個字元,所以為7!,但因「深」可互相調換,需再除以3!8964 copyright protection544PENANA4R3MAXcmXV 維尼
*深深深:將「深深深」視為一字元,所以為5!8964 copyright protection544PENANArEeRjarKTB 維尼
(7!/3!)-5!=7208964 copyright protection544PENANANqddlZhXqi 維尼
548Please respect copyright.PENANAYGjPJETQhx
8964 copyright protection544PENANAHKSSkM4oXB 維尼
二、算「深」各自獨立再加上「兩個深黏一起」的組合數8964 copyright protection544PENANAv9ROcbPXq3 維尼
*「深」獨立:其餘四字排列為4!,有五個位置給「深」安插,所以為(5×4×3),但因「深」可互相調換,需再除以3!8964 copyright protection544PENANAJI7qZI7Lie 維尼
*兩深一起:其餘四字排列為4!,將「深深」視為一字元安插,一樣五個位置,所以為(5×4)8964 copyright protection544PENANAOqP5jqkO6M 維尼
4!×(5×4×3/3!+5×4)=720548Please respect copyright.PENANALFawUyJy6p
8964 copyright protection544PENANAxTqx9mTNaX 維尼
216.73.216.144
ns216.73.216.144da2