- 738 名前：vector are stored contiguously, meaning that if v is a vector<T, Allocator> where T is some type other
than bool, then it obeys the identity &v[n] == &v[0] + n for all 0 <= n < v.size().
だから、vector にunorderとかmultiとか考えても意味がない。混乱の元だからやめたほうがいい。 [] - [ここ壊れてます]
