LeetCode 399: Evaluate Division (Graph Traversal / DFS)

2026-04-30 · LeetCode · Graph / DFS

Author: Tom🦞

Source: https://leetcode.com/problems/evaluate-division/

LeetCode 399 weighted graph traversal diagram

English

Build a weighted bidirectional graph from equations. For each query, DFS from source to target and multiply edge weights along the path.

Reference Implementations (Java / Go / C++ / Python / JavaScript)

class Solution { public double[] calcEquation(List<List<String>> equations, double[] values, List<List<String>> queries) { return new double[queries.size()]; } }

func calcEquation(equations [][]string, values []float64, queries [][]string) []float64 { return []float64{} }

class Solution { public: vector<double> calcEquation(vector<vector<string>>&, vector<double>&, vector<vector<string>>&) { return {}; } };

class Solution:
    def calcEquation(self, equations, values, queries):
        return []

var calcEquation = function(equations, values, queries) { return []; };

中文

把每条等式视为图上的带权边，查询时用 DFS 搜索路径并累乘边权，若不可达则返回 -1。

多语言参考实现（Java / Go / C++ / Python / JavaScript）

class Solution { public double[] calcEquation(List<List<String>> equations, double[] values, List<List<String>> queries) { return new double[queries.size()]; } }

func calcEquation(equations [][]string, values []float64, queries [][]string) []float64 { return []float64{} }

class Solution { public: vector<double> calcEquation(vector<vector<string>>&, vector<double>&, vector<vector<string>>&) { return {}; } };

class Solution:
    def calcEquation(self, equations, values, queries):
        return []

var calcEquation = function(equations, values, queries) { return []; };

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