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No Plagiarism!Imv5ayED48yinFOBnrMwposted on PENANA 「庭院深深深幾許,三深不能排一起」有兩種解法。8964 copyright protection554PENANA3CGXDZtw3z 維尼
558Please respect copyright.PENANAyOQRxF2FxJ
8964 copyright protection554PENANAA4jbrn2Igd 維尼
一、算「全部排列方式」再扣掉「深深深一起」的組合數8964 copyright protection554PENANA8LRHNCOa5i 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 protection554PENANAiL6S6eQ3hC 維尼
*深深深:將「深深深」視為一字元,所以為5!8964 copyright protection554PENANAE0g9pJyOHY 維尼
(7!/3!)-5!=7208964 copyright protection554PENANA6R8Y0q0kVx 維尼
558Please respect copyright.PENANABD6VOOlvKY
8964 copyright protection554PENANAiNRROuyQUo 維尼
二、算「深」各自獨立再加上「兩個深黏一起」的組合數8964 copyright protection554PENANABSQj1ta6Wt 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 protection554PENANA8SvY40C0d2 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 protection554PENANARsUv1lmviF 維尼
4!×(5×4×3/3!+5×4)=720558Please respect copyright.PENANA72Hni9ITbs
8964 copyright protection554PENANAIaSFJAotzr 維尼
216.73.216.146
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