→ doom8199 :前面是指不超過 100的四個正整數排序在一起 03/28 22:57
→ doom8199 :則這四個正整數有包含連續三正整數 的所有可能有多少 03/28 22:59
how many 4-permutations of the positive integers
not exceeding 100 contain three consecutive integers k k+1 k+2
in the correct order
a)where these consecutive integers can perhaps be separated by other integers
in the permutations?
ANS=37927
b)where there in consecutive positions in the permutations?
ANS=18915
英文太差...真的看不懂題目想表達的意思
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