Merge pull request #2704 from tahzeer/patch-3

Create 0399-evaluate-division.cpp

Author: felivalencia3

Diff for: cpp/0399-evaluate-division.cpp

@@ -0,0 +1,57 @@
+class Solution {
+    unordered_map<string, vector<pair<string, double>>> graph;
+    unordered_map<string, bool> visited;
+    double queryAns;
+
+public:
+    bool dfs(string startNode, string endNode, double runningProduct){
+        if(graph.find(startNode) == graph.end() || graph.find(endNode) == graph.end()) {
+            return false;
+        }
+        
+        if(startNode == endNode && graph.find(startNode)!=graph.end()) {
+            queryAns = runningProduct;
+            return true;
+            
+        }
+        
+        bool tempAns = false;
+        visited[startNode] = true;
+        
+        for(int i = 0; i < graph[startNode].size(); i++){
+            if(!visited[graph[startNode][i].first]){
+                tempAns = dfs(graph[startNode][i].first, endNode, runningProduct*graph[startNode][i].second);
+                if(tempAns){
+                    break;
+                }
+            }
+        }
+        visited[startNode] = false;
+        
+        return tempAns;
+    }
+    
+    vector<double> calcEquation(vector<vector<string>>& equations, vector<double>& values, vector<vector<string>>& queries) {
+        int n = equations.size(), m = queries.size();
+        vector<double> ans(m);
+        
+        for(int i = 0; i < n ; i++){
+            
+            graph[equations[i][0]].push_back({equations[i][1], values[i]});
+            graph[equations[i][1]].push_back({equations[i][0], 1/values[i]});
+            visited[equations[i][0]] = false;
+            visited[equations[i][1]] = false;
+
+        }
+        
+        for(int i = 0; i < m ; i++){
+            
+            queryAns = 1;
+            bool pathFound = dfs(queries[i][0], queries[i][1], 1);            
+            if(pathFound) ans[i] = queryAns;
+            else ans[i] = -1;
+            
+        }
+        return ans;
+    }
+};