Day 29: Count goodStrings #22
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jabagawee
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May 9, 2017
| constructing a good string, we should not place another letter 'a' in the same | ||
| good string. And likewise, we shouldn't place letters into the good string | ||
| if they are lexicographically less than the characters that precede it. | ||
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i think you misread the 3rd rule. note that it says "exactly one" and not "every"
jabagawee
reviewed
May 9, 2017
| return factorial(n) / (factorial(n-r) * factorial(r)) | ||
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| def goodStringsCount(n): | ||
| return nChooseR(26, n) * (2**n - n - 1) |
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this solution works but it doesn't follow from the examples in your ideas section
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