EvaluateDivision.py

def dfs(self, node: str, dest: str, gr: dict, vis: set, ans: List[float], temp: float) -> None:
        if node in vis:
            return

        vis.add(node)
        if node == dest:
            ans[0] = temp
            return

        for ne, val in gr[node].items():
            self.dfs(ne, dest, gr, vis, ans, temp * val)

def buildGraph(self, equations: List[List[str]], values: List[float]) -> dict:
    gr = {}

    for i in range(len(equations)):
        dividend, divisor = equations[i]
        value = values[i]

        if dividend not in gr:
            gr[dividend] = {}
        if divisor not in gr:
            gr[divisor] = {}

        gr[dividend][divisor] = value
        gr[divisor][dividend] = 1.0 / value

    return gr

def calcEquation(self, equations: List[List[str]], values: List[float], queries: List[List[str]]) -> List[float]:
    gr = self.buildGraph(equations, values)
    finalAns = []

    for query in queries:
        dividend, divisor = query

        if dividend not in gr or divisor not in gr:
            finalAns.append(-1.0)
        else:
            vis = set()
            ans = [-1.0]
            temp = 1.0
            self.dfs(dividend, divisor, gr, vis, ans, temp)
            finalAns.append(ans[0])

    return finalAns