Create 2493.Divide-Nodes-Into-the-Maximum-Number-of-Groups.cpp

BFS/2493.Divide-Nodes-Into-the-Maximum-Number-of-Groups/2493.Divide-Nodes-Into-the-Maximum-Number-of-Groups.cpp

@@ -0,0 +1,73 @@
+class Solution {
+    int Father[505];
+    int FindFather(int x)
+    {
+        if (Father[x]!=x)
+            Father[x] = FindFather(Father[x]);
+        return Father[x];
+    }
+
+    void Union(int x, int y)
+    {
+        x = Father[x];
+        y = Father[y];
+        if (x<y) Father[y] = x;
+        else Father[x] = y;
+    }     
+
+    vector<int>next[505];
+
+public:
+    int magnificentSets(int n, vector<vector<int>>& edges) 
+    {
+        for (int i=1; i<=n; i++)
+            Father[i] = i;
+        for (auto edge: edges)
+        {
+            int a = edge[0], b = edge[1];
+            if (FindFather(a)!=FindFather(b))
+                Union(a,b);
+            next[a].push_back(b);
+            next[b].push_back(a);
+        }
+
+        unordered_map<int,vector<int>>groups;
+        for (int i=1; i<=n; i++)
+            groups[FindFather(i)].push_back(i);
+
+        int ret = 0;
+
+        for (auto& [_, nodes]: groups)
+        {            
+            int ans = 0;
+            for (int start: nodes)
+            {                
+                unordered_map<int,int>level;
+                level[start] = 1;
+                queue<pair<int,int>>q;
+                q.push({start, 1});
+
+                while (!q.empty())
+                {
+                    auto [cur, d] = q.front();
+                    q.pop();
+                    ans = max(ans, d);
+
+                    for (int nxt: next[cur])
+                    {
+                        if (level.find(nxt)==level.end())
+                        {
+                            level[nxt] = d+1;
+                            q.push({nxt, d+1});
+                        }
+                        else if (level[nxt] == d)
+                            return -1;                            
+                    }
+                }                
+            }
+            ret += ans;
+        }
+
+        return ret;        
+    }
+};