Lib/木の直径

重み付き

code:cpp

int graph_diameter(vector<vector<pair<int,int>>> &vec){

//0-indexed

queue<pair<int,int>> que;

vector<bool> is_searched(vec.size(),false);

que.push(make_pair(0,0));

int max_d = 0;

int max_e = 0;

while(!que.empty()){

int e = que.front().first;

int distance = que.front().second;

if(max_d<distance){

max_d = distance;

max_e = e;

}

que.pop();

}

}

}

fill(is_searched.begin(),is_searched.end(),false);

que.push(make_pair(max_e,0));

max_d = 0;

max_e = 0;

while(!que.empty()){

int e = que.front().first;

int distance = que.front().second;

if(max_d<distance){

max_d = distance;

max_e = e;

}

que.pop();

}

}

}

return max_d;

}

重みなし

code:cpp

ll getfar(vector<vector<ll>> g,ll start,vector<ll> &d){

ll n = g.size();

vector<bool> is_see(n,false);

queue<pair<ll,ll>> que;

que.push({start,0});

ll mdist = 0;

ll mdistp = 0;

while(!que.empty()){

que.pop();

if(mdist < dist){

mdist = dist;

mdistp = p;

}else if(mdist == dist){

chmax(mdistp,p);

}

que.push({next,dist+1});

}

}

}

return mdistp;

}

古いので書き換えたい