Create 3387.Maximize-Amount-After-Two-Days-of-Conversions.cpp

Author: wisdompeak

Graph/3387.Maximize-Amount-After-Two-Days-of-Conversions/3387.Maximize-Amount-After-Two-Days-of-Conversions.cpp

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+class Solution {
+    unordered_map<string,int>name2idx;
+public:
+    double maxAmount(string initialCurrency, vector<vector<string>>& pairs1, vector<double>& rates1, vector<vector<string>>& pairs2, vector<double>& rates2) 
+    {
+        unordered_set<string>Set;
+        for (auto pair: pairs1)
+        {
+            Set.insert(pair[0]);
+            Set.insert(pair[1]);
+        }
+        for (auto pair: pairs2)
+        {
+            Set.insert(pair[0]);
+            Set.insert(pair[1]);
+        }
+        int idx = 0;
+        for (string s: Set)
+            name2idx[s] = idx++;
+            
+        
+        int n = name2idx.size();
+        vector<vector<double>> dist1 = floyd(pairs1, rates1);
+        vector<vector<double>> dist2 = floyd(pairs2, rates2);
+        
+        int s = name2idx[initialCurrency];
+        double ret = 1.0;
+        for (int i=0; i<n; i++)
+            ret = max(ret, 1.0*dist1[s][i]*dist2[i][s]);
+        return ret;
+    }
+    
+    vector<vector<double>> floyd(vector<vector<string>>& pairs, vector<double>& rates)
+    {
+        int n = name2idx.size();
+        vector<vector<double>>dist(n, vector<double>(n,0));
+        for (int i=0; i<n; i++)
+            dist[i][i] = 1.0;
+        for (int i=0; i<rates.size(); i++)
+        {
+            int a = name2idx[pairs[i][0]];
+            int b = name2idx[pairs[i][1]];
+            double t = rates[i];
+            
+            for (int i=0; i<n; i++)
+                for (int j=0; j<n; j++)
+                {
+                    dist[i][j] = max(dist[i][j], dist[i][a]*t*dist[b][j]);
+                    dist[i][j] = max(dist[i][j], dist[i][b]*1.0/t*dist[a][j]);
+                    
+                    dist[j][i] = max(dist[j][i], dist[j][a]*t*dist[b][i]);
+                    dist[j][i] = max(dist[j][i], dist[j][b]*1.0/t*dist[b][i]);
+                }                        
+        }
+        return dist;
+    }
+    
+    
+};