45分钟coding.
- 压缩⼀个string，有连续出现同⼀个char的话变成char+出现次数。loop⼀遍就好。
- Given a list of names, if a name is shown before, make it name1,name2…depending on how many duplicates.
- Given (a,b), it can only reach either (a+b,b) or (a,a+b). Ask if it is possible to go from (a,b) to (c,d).