Evaluate Division Solution

function calcEquation(equations, values, queries):
    parent = {}
    weight = {}

    function find(x):
        if x not in parent:
            parent[x] = x
            weight[x] = 1.0
        if parent[x] != x:
            origParent = parent[x]
            parent[x] = find(parent[x])
            weight[x] *= weight[origParent]
        return parent[x]

    function union(a, b, val):
        rootA = find(a)
        rootB = find(b)
        if rootA != rootB:
            parent[rootA] = rootB
            weight[rootA] = weight[b] * val / weight[a]

    for i from 0 to equations.length - 1:
        (a, b) = equations[i]
        val = values[i]
        union(a, b, val)

    result = []
    for each (a, b) in queries:
        if a not in parent or b not in parent:
            result.add(-1.0)
        else if find(a) != find(b):
            result.add(-1.0)
        else:
            result.add(weight[a] / weight[b])
    return result