PAT (Advanced Level) Practice 1023 Have Fun with Numbers(20分)【字符串】
Noticethatthenumber123456789isa9-digitnumberconsistingexactlythenumbersfrom1to9,withnoduplication.Doubleitwewillobtain246913578,whichhappenstobeanother9-digitnumberconsistingexactlythenumbersfrom1to9,