class Solution {
public:
    vector<double> calcEquation(vector<vector<string>>& equations, vector<double>& values, vector<vector<string>>& queries) {
        //把出现的字符映射到数字
        int n = 0;
        unordered_map<string, int>var;
        int m = equations.size();
        for(int i = 0; i < m; i++){
            if(var.find(equations[i][0])==var.end()){
                var[equations[i][0]] = n++;
            }
            if(var.find(equations[i][1])==var.end()){
                var[equations[i][1]] = n++;
            }
        }
        //建图, n*n邻接矩阵
        vector<vector<double>>G(n,vector<double>(n,-1.0));
        for(int i = 0; i < m; i++){
            int u = var[equations[i][0]], v = var[equations[i][1]];
            G[u][v] = values[i];
            G[v][u] = 1.0/values[i];
        }
        //floyed，处理出任意点对间的距离
        for(int k = 0; k < n; k++){
            for(int i = 0...