LeetCode 351: Android Unlock Patterns
Problem Restatement We have a 3 x 3 Android lock screen. The dots are numbered like this: 1 2 3 4 5 6 7 8 9 Given two integers m and n , count how many valid unlock patterns have length at least m and at most n . A pattern is a sequence of distinct dots. A move from one dot to another is valid if either: The line...