Question

Given a graph and a starting vertex, count the number of nodes a specified distance away. C++ Programming

Answer 1

Qo.

ANS:

C++ Code:

int countNodeDistance(vector<int> graph[], bool assignMark[], int node, vector<int>& distance)
{
   int lastvisited;
   queue<int> q;
   q.push(node);
   distance[node] = 0;
   while (!q.empty())
   {
       node = q.front();   q.pop();
       if (assignMark[node])
           lastvisited = node;
       for (int i = 0; i < graph[node].size(); i++)
       {
           int v = graph[node][i];
           if (distance[v] == -1)
           {
               distance[v] = distance[node] + 1;
               q.pnodesh(v);
           }
       }
   }
   return lastvisited;
}
int nodeDistancevisited(int edgeGraph[][2], int v, int assignvisited[], int N, int K)
{
   v = v + 1;
   vector<int> graph[v];

   int node, v;     
   for (int i = 0; i < (v - 1); i++)
   {
       node = edgeGraph[i][0];
       v = edgeGraph[i][1];

       graph[node].push_back(v);
       graph[v].push_back(node);
   }
   bool assignMark[v] = {false};
   for (int i = 0; i < N; i++)
   {
       assignMark[assignvisited[i]] = true;
   }
   vector<int> tmp(v, -1), dl(v, -1), dr(v, -1);
   node = countNodeDistance(graph, assignMark, 0, tmp);
   node = countNodeDistance(graph, assignMark, node, dl);
   countNodeDistance(graph, assignMark, node, dr);
   int rest = 0;
   for (int i = 0; i < v; i++)
   {
       if (dl[i] <= K && dr[i] <= K)
           rest++;
   }
   return rest;
}

// main or driver program
int main()
{
   int edgeGraph[][2] =
   {
       {1, 0}, {0, 3}, {0, 8}, {2, 3},
       {3, 5}, {3, 6}, {3, 7}, {4, 5},
       {5, 9}
   };
   int v = sizeof(edgeGraph) / sizeof(edgeGraph[0]);
  
   int assignvisited[] = {1, 2, 4};
   int N = sizeof(assignvisited) / sizeof(assignvisited[0]);

   int K = 3;
   cout << nodeDistancevisited(edgeGraph, v, assignvisited, N, K);
   return 0;
}

OUTPUT:

6

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THANKS!!