使用向量和队列实现BFS，按照CLRS算法在C程序中的实现

begin   for each vertex u in G.V - {s}, do      u.color := white      u.d := infinity      u.p := NIL   done   s.color := green   s.d := 0   s.p := NIL   Q := NULL   insert s into Q   while Q is not null, do      u = delete from Q      for each v in adjacent to u, do         if v.color = white            v.color := green            v.d := u.d + 1            v.p := u            insert v into Q         end if      done      u.color = dark_green   doneend

#include#include#includeusing namespace std;vector colour;vector dist;vector par;void addEdge(vector  g[], int u, int v) { //add edge to form the graph   g[u].push_back(v);   g[v].push_back(u);}void BFS(vector  g[], int s) {   queue q;   q.push(s); //insert source   dist[s] = 0;   colour[s] = "gray";   while (!q.empty()) {      int u = q.front(); //top element from queue, then delete it      q.pop();      cout << u << " ";      for (auto i = g[u].begin(); i != g[u].end(); i++) {         if (colour[*i] == "white") { //white is unvisited node            colour[*i] = "gray"; //gray is visited but not completed            dist[*i] = dist[u] + 1;            par[*i] = u;            q.push(*i);         }      }      colour[u] = "black"; //black is completed node   }}void BFSAlgo(vector  g[], int n) {   colour.assign(n, "white"); //put as unvisited   dist.assign(n, 0);   par.assign(n, -1);   for (int i = 0; i < n; i++)      if (colour[i] == "white")   BFS(g, i);}int main() {   int n = 7;   vector  g[n];   addEdge(g, 0, 1);   addEdge(g, 0, 2);   addEdge(g, 1, 3);   addEdge(g, 1, 4);   addEdge(g, 2, 5);   addEdge(g, 2, 6);   BFSAlgo(g, n);}

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