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No Plagiarism!W5P6ANx27qXvGNEViYaHposted on PENANA 「庭院深深深幾許,三深不能排一起」有兩種解法。8964 copyright protection546PENANAkALfWF9GLA 維尼
550Please respect copyright.PENANAOvf8YwXPFF
8964 copyright protection546PENANAbAcnIGc007 維尼
一、算「全部排列方式」再扣掉「深深深一起」的組合數8964 copyright protection546PENANAy1oFakPW4U 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 protection546PENANAX64MGyjECP 維尼
*深深深:將「深深深」視為一字元,所以為5!8964 copyright protection546PENANAE1qcUR28ZK 維尼
(7!/3!)-5!=7208964 copyright protection546PENANAoy1iAnQOS4 維尼
550Please respect copyright.PENANA3G7Ow2i2FD
8964 copyright protection546PENANAeBNoANXdAU 維尼
二、算「深」各自獨立再加上「兩個深黏一起」的組合數8964 copyright protection546PENANAbV4BCPv7vS 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 protection546PENANAAymGaje9A2 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 protection546PENANAVbFNIhaHjI 維尼
4!×(5×4×3/3!+5×4)=720550Please respect copyright.PENANARYsLqNKIYo
8964 copyright protection546PENANABX9NZUpPCw 維尼
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