STL类:stack,queue,deque,priority_queue,map,set,multiset,bitset,vector,hash
函数类:min,max,swap,sqrt,log,reverse,lower_bound,upper_bound,sort,rand,next_permutation,prev_permutation,unique,random_shuffle
,shuffle,time,clock
符号类:x+x,x++,[x]
变量名类:x1,y1,x0,y0
关键字冲撞,CE两行泪。