Template classes like DSU for Leetcode Problems

LeetcodePythonTemplates.py

class DSU:
    def __init__(self, n = 1000000000):
        self.parent = [i for i in range(n)]
        self.rank = [1] * n
    def make_set(self,u):
        self.parent[u] = u
        self.rank[u] = 1
    def find_set(self,u):
        if self.parent[u] == u:
            return u
        self.parent[u] = self.find_set(self.parent[u]) # path compresssion so we don't recompute
        return self.parent[u]
    def union_sets(self, u, v):
        u = self.find_set(u) # because we have to work on their roots
        v = self.find_set(v) # since root represents the entire set
        if u != v:
            if self.rank[u] < self.rank[v]:
                u, v = v, u # make sure v is smaller
            self.parent[v] =  u
            self.rank[u] += self.rank[v] # sum of size (or += 1 is rank is depth)            
        # return self.rank[u] # just helpful sometimes