// may be it not working perfectly :(, but it very fast
func (ts *threesum) TriplesCountFast() int {
is := sort.Insertion{ts.nums}
is.Sort()
cnt := 0
for i, vi := range is.A {
for j, vj := range is.A[i+1:] {
bs := search.Binary{A: is.A[j+1:], X: -(vi + vj)}
k := bs.Iterative(0, len(bs.A)-1)
if k > j {
cnt += 1
}
}
}
return cnt
}
func (ts *twosum) CountFast() int {
is := sort.Insertion{ts.ids}
is.Sort()
ts.ids = is.A
cnt := 0
for i, v := range ts.ids {
bs := search.Binary{A: ts.ids, X: -v}
index := bs.Recursive(0, len(bs.A)-1)
if index > i {
cnt += 1
}
}
return cnt
}