hihoCoder 1067 最近公共祖先·二

#include <bits/stdc++.h>using namespace std;map<string,int> nameMap;string names[100005];struct node{int pa;vector<int> son;vector<pair<int,int> > qu;node() : pa(-1){}}no[100005];int ans[100005];int findset(int x){    if(x != no[x].pa)        no[x].pa = findset(no[x].pa);    return no[x].pa;}void dfs(int f){no[f].pa = f;    int len = no[f].son.size();for(int i=0 ;i<len;i++){int index = no[f].son[i];dfs(index);no[index].pa  = f;}int qlen = no[f].qu.size();for(int i=0; i<qlen; i++){pair<int, int> p = no[f].qu[i];if(no[p.first].pa != -1)ans[p.second] = findset(p.first);}}int main(){int N,M;scanf("%d",&N);for(int i=0; i<N; i++){string fa,son;cin>>fa>>son;if(nameMap.find(fa) == nameMap.end())nameMap[fa] = nameMap.size();if(nameMap.find(son) == nameMap.end())nameMap[son] = nameMap.size();int nf = nameMap[fa], ns = nameMap[son];names[nf] = fa;names[ns] = son;no[nf].son.push_back(ns);}scanf("%d",&M);for(int i=0; i<M; i++){string qu1,qu2;cin>>qu1>>qu2;int n1 = nameMap[qu1], n2 = nameMap[qu2];no[n1].qu.push_back(make_pair(n2,i));no[n2].qu.push_back(make_pair(n1,i));}dfs(1);for(int i = 0; i < M ; i++)//puts(names[ans[i]].c_str());cout<<names[ans[i]]<<endl;return 0;}