most-stones.py

class Solution:
    def removeStones(self, stones):
        t = [-1] * len(stones)
        xs, ys = {}, {}
        for i, p in enumerate(stones):
            x, y = p
            if x in xs: self.onion(xs[x], i, t)
            else: xs[x] = i
            if y in ys: self.onion(ys[y], i, t)
            else: ys[y] = i
        return len(stones) - sum([1 for p in t if p < 0])
        
    def onion(self, a, b, t):
        a, b = self.root(a, t), self.root(b, t)
        if a == b: return
        if t[a] > t[b]: a, b = b, a
        t[b] = a
    
    def root(self, a, t):
        if t[a] < 0: return a
        t[a] = self.root(t[a], t)
        return t[a]