摘要：
Before being an ubiquous communications gadget, a mobilewas just a structure made of strings and wires suspendingcolourfull things. This kind of mobil 阅读全文
摘要：
The SUM problem can be formulated as follows: given four lists A;B;C;D of integer values, computehow many quadruplet (a; b; c; d) 2 AB C D are such 阅读全文