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  1. #include <iostream>
  2. #include <string>
  3. #include <vector>
  4. #include <map>
  5. #include <queue>
  6.  
  7. using namespace std;
  8.  
  9. int main() {
  10.     int n, m;
  11.  
  12.     if (!(cin >> n >> m)) return 0;
  13.  
  14.     map<string, vector<string>> adjList;
  15.     map<string, int> dist;
  16.     map<string, string> parent;
  17.     map<string, bool> visited; 
  18.  
  19.     for (int i = 0; i < m; i++) {
  20.         string u, v;
  21.         cin >> u >> v;
  22.  
  23.         if (u == v) {
  24.             adjList[u]; 
  25.         } else {
  26.             adjList[u].push_back(v);
  27.             adjList[v].push_back(u); 
  28.         }
  29.     }
  30.  
  31.     string tag, assemblyPoint;
  32.     cin >> tag >> assemblyPoint; 
  33.     adjList[assemblyPoint];      
  34.  
  35.     for (auto const& pair : adjList) {
  36.         visited[pair.first] = false;
  37.         dist[pair.first] = -1;
  38.     }
  39.  
  40.     queue<string> q;
  41.     dist[assemblyPoint] = 0;
  42.     visited[assemblyPoint] = true;
  43.     q.push(assemblyPoint);
  44.  
  45.     while (!q.empty()) {
  46.         string current = q.front();
  47.         q.pop();
  48.  
  49.         for (const string& neighbor : adjList[current]) {
  50.             if (!visited[neighbor]) {
  51.                 visited[neighbor] = true;
  52.                 dist[neighbor] = dist[current] + 1;
  53.                 parent[neighbor] = current;
  54.                 q.push(neighbor);
  55.             }
  56.         }
  57.     }
  58.  
  59.     for (auto const& pair : adjList) {
  60.         string point = pair.first;
  61.  
  62.         if (point == assemblyPoint) continue; 
  63.  
  64.         if (!visited[point]) {
  65.             cout << "Point: " << point << " Reachable: No Steps: - Route: No path exists\n";
  66.         } else {
  67.             cout << "Point: " << point << " Reachable: Yes Steps: " << dist[point] << " Route: ";
  68.  
  69.             string curr = point;
  70.             while (curr != assemblyPoint) {
  71.                 cout << curr << " -> ";
  72.                 curr = parent[curr];
  73.             }
  74.             cout << assemblyPoint << "\n";
  75.         }
  76.     }
  77.  
  78.     return 0;
  79. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/OICHqQ
language:
C++ (gcc 8.3)
created:
15 hours ago
visibility:
public

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