University Codesprint 3

Black_White_Tree_C++.cpp

@@ -0,0 +1,88 @@
+#include<bits/stdc++.h>
+using namespace std ;
+
+int visited[100009] , n ,point ,c , col1 , a[100009] , final_ans , present[100009] ; 
+vector < int >adj[100009] , ans[2][100009] ; 
+
+int dfs(int i , int col)
+{
+    if(visited[i])
+    return  -1 ; 
+
+    visited[i]= 1 ; 
+
+    int tot =0 ; 
+
+    for(int j =0 ;j<adj[i].size() ; j++)
+    {
+        int val = dfs(adj[i][j] , col) ; 
+
+        if(val >0)
+        {
+            tot+=val ; 
+           // cout<<adj[i][j]<<" "<<i<<" "<<val<<" "<<tot<<" "<<col<<"df\n" ;
+            ans[col][i].push_back(adj[i][j]) ; 
+        }
+    }
+
+    if(a[i] == col)
+        tot++ ; 
+    else
+        tot-- ; 
+
+    if(final_ans < tot)
+    {
+        final_ans = tot; 
+        col1 = col ; 
+        point = i ;  
+    }
+    return tot ; 
+}
+
+void dfs1(int i , int vis)
+{
+//	cout<<i<<"\n ";
+c++ ;  
+        present[i] = 1; 
+    for(int j = 0 ; j<ans[col1][i].size() ; j++)
+    {
+        if(!present[ans[col1][i][j]])
+        dfs1(ans[col1][i][j] , vis) ; 
+    }
+}
+int main()
+{
+    cin>>n ; 
+
+    for(int i = 1; i <=n ; i++)
+        cin>>a[i] ; 
+
+    for(int i =0 ; i<n-1; i++)
+    {
+        int u , v ; 
+        cin>>u>>v ; 
+
+        adj[u].push_back(v) ; 
+        adj[v].push_back(u) ; 
+    }
+
+    int t = 0 ;
+    dfs(1 , 0 ) ; 
+
+    memset(visited , 0 , sizeof(visited));
+
+    dfs(1 , 1) ;
+
+    cout<<final_ans<<"\n" ; 
+
+    c = 0; 
+
+    dfs1(point , 0 ) ; 
+    cout<<c<<"\n" ; 
+
+    for(int i = 1; i <=n ; i++)
+    if(present[i])
+    cout<<i<<" ";
+
+    return 0 ; 
+}