x
No Plagiarism!JMKtDHkOlobxxo6HBkfgposted on PENANA 「庭院深深深幾許,三深不能排一起」有兩種解法。8964 copyright protection444PENANArY2TQsvj3K 維尼
448Please respect copyright.PENANA7sl5qVA0lp
8964 copyright protection444PENANAiEOu7LUivt 維尼
一、算「全部排列方式」再扣掉「深深深一起」的組合數8964 copyright protection444PENANAoT5oKos4gk 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 protection444PENANAPMeS5awFo0 維尼
*深深深:將「深深深」視為一字元,所以為5!8964 copyright protection444PENANA43MkEaY6bm 維尼
(7!/3!)-5!=7208964 copyright protection444PENANAGRIv65TYq3 維尼
448Please respect copyright.PENANAci17G2f9Ha
8964 copyright protection444PENANArLhtIqL0yD 維尼
二、算「深」各自獨立再加上「兩個深黏一起」的組合數8964 copyright protection444PENANAqcGjjOjm4f 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 protection444PENANAp3jm0ZmB8r 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 protection444PENANATtQ26R4UQW 維尼
4!×(5×4×3/3!+5×4)=720448Please respect copyright.PENANAKuIdEAwoEu
8964 copyright protection444PENANALy7ZhO2cYK 維尼
3.133.100.106
ns3.133.100.106da2