学步园

 1. There are two types of professional wrestlers: "good guys" and "bad guys." Between any pair
of professional wrestlers, there may or may not be a rivalry. Suppose we have n professional
wrestlers and we have a list of r pairs of wrestlers for which there are rivalries. Give an O(n +
r)-time algorithm that determines whether it is possible to designate some of the wrestlers as
good guys and the remainder as bad guys such that each rivalry is between a good guy and a
bad guy. If is it possible to perform such a designation, your algorithm should produce it.

这个月太忙，都没时间写博客

刚写了离散作业，实际是BFS的变体

直接上代码

bool Graph::designation(int s){
 initBFS(); 

 graNodes[s].color=GRAY;
 graNodes[s].level=0;
 
 deque<Node*> blocks;
 blocks.clear();

 blocks.push_back(&graNodes[s]);
 Node* tempNode;
 while(!blocks.empty()){
  tempNode=blocks.front();
  blocks.pop_front();
  cout<<"*"<<tempNode->nodeID<<"*";
  for (vector<Node*>::iterator ivl = (tempNode->adjList).begin(); ivl != (tempNode->adjList).end(); ivl++) {
   if(((*ivl)->color)!=WHITE){
    if(((*ivl)->level%2)==(tempNode->level%2)){    
     cout<<"节点"<<(*ivl)->nodeID<<"和节点"<<(tempNode->nodeID)<<"不能满足条件"<<endl;
     return false;
    }
   }
   else{
    (*ivl)->color=GRAY;
    (*ivl)->level=tempNode->level+1;
    (*ivl)->pre=tempNode->nodeID;
    blocks.push_back(*ivl);
   }
   
  }
  tempNode->color=BLACK;
 }
 

 return true;
}