Question

string probability programming

Answer 1

Assuming "complete randomness" and given a string with a length of 20 characters where each character may be one of 62 possible characters:

What are the total number of combinations possible? (Guessing 20 to the power of 62.)Also, if new strings are randomly selected one after another and added to a list of strings selected so far, how many strings must be selected before the chance of selecting a string that has already been selected is below 1-in-100000 (10−5" role="presentation" style="box-sizing: inherit; margin: 0px; padding: 0px; border: 0px; font-style: normal; font-variant: inherit; font-weight: normal; font-stretch: inherit; line-height: normal; font-family: inherit; font-size: 15px; vertical-align: baseline; display: inline; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">10−510−5)?

Note: 62 comes from: numeric digits (0-9), uppercase letters (A-Z), and lowercase letters (a-z).