class UnionFind(): def __init__(self, n): self.n = n self.parents = [-1] * n def find(self, x): if self.parents[x] < 0: return x else: self.parents[x] = self.find(self.parents[x]) return self.parents[x] def union(self, x, y): x = self.find(x) y = self.find(y) if x == y: return if self.parents[x] > self.parents[y]: x, y = y, x self.parents[x] += self.parents[y] self.parents[y] = x def same(self, x, y): return self.find(x) == self.find(y) def roots(self): return [i for i, x in enumerate(self.parents) if x < 0] def num_roots(self): return len([i for i, x in enumerate(self.parents) if x < 0]) def members(self, x): root = self.find(x) return [i for i in range(self.n) if self.find(i) == root] def num_members(self,x): return abs(self.parents[self.find(x)]) def __str__(self): return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots()) from bisect import * def uni(i,A,B): ind = bisect_left(X,X[i]+A) while indX[ind]: if ind>=N-1: break ind = uni(i,A,B) else: uf.union(i,ind) while ind+1