2019 day 4 init

2019/day04/README.org

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+** --- Day 4: Secure Container ---
+You arrive at the Venus fuel depot only to discover it's protected by a
+password. The Elves had written the password on a sticky note, but
+someone threw it out.
+
+However, they do remember a few key facts about the password:
+
+- It is a six-digit number.
+- The value is within the range given in your puzzle input.
+- Two adjacent digits are the same (like =22= in =122345=).
+- Going from left to right, the digits /never decrease/; they only ever
+  increase or stay the same (like =111123= or =135679=).
+
+Other than the range rule, the following are true:
+
+- =111111= meets these criteria (double =11=, never decreases).
+- =223450= does not meet these criteria (decreasing pair of digits
+  =50=).
+- =123789= does not meet these criteria (no double).
+
+/How many different passwords/ within the range given in your puzzle
+input meet these criteria?
+
+Your puzzle input is =130254-678275=.