摘要：
To brighten up the gala dinner of the IOI'98 we have a set of N (10 <= N <= 100) colored lamps numbered from 1 to N.The lamps are connected to four buttons:Button 1: When this button is pressed, all the lamps change their state: those that are ON are turned OFF and those that are OFF are t 阅读全文
摘要：
Runaround numbers are integers with unique digits, none of which is zero (e.g., 81362) that also have an interesting property, exemplified by this demonstration:If you start at the left digit (8 in our number) and count that number of digits to the right (wrapping back to the first digit when no dig 阅读全文