class Solution {
private:
    unordered_map<string, int> suppHash, memo; 
    unordered_map<string, vector<string> > recipeHash; 
public:
    vector<string> findAllRecipes(vector<string>& recipes, vector<vector<string>>& ingredients, vector<string>& supplies) {
        vector<string> res; 
        for (string supply : supplies) 
            suppHash[supply]++; 
        for (int i = 0; i < recipes.size(); i++) {
            recipeHash[recipes[i]] = ingredients[i]; 
        }
        for (string rec : recipes) {
            if (dfs(rec)) 
                res.push_back(rec); 
        }
        return res; 
    }
    bool dfs(string recipe) {
        if (memo[recipe]) 
            return memo[recipe] == 1 ? true : false; 
        vector<string> recList = recipeHash[recipe]; 
        for (string rec : recList) {
            if (!suppHash[rec]) {
                if (recipeHash.find(rec) == recipeHash.end() && !dfs(rec)) {
                    memo[rec] = -1; 
                    return false; 
                } 
            } 
        }  
        memo[recipe] = 1; 
        return true; 
    }
};