2016夏季练习——LCA

来源：POJ1470

找了多少都是用的TATJAN，但是我是用的倍增法做的这个题

PS: DEBUG好辛苦

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
using namespace std;
int n,Q;
int l,r;
const int MAXN = 910;
vector<int>tree[MAXN];
struct Node{
	int k;
	int id;
	Node():k(0),id(0){}
}ans[MAXN];
bool son[MAXN];
int dp[MAXN][11];
int depth[MAXN];
void dfs(int cur,int pre,int d){
	//cout<<cur<<" "<<pre<<" "<<d<<endl;
	depth[cur]=d;
	dp[cur][0]=pre;
	//if(cur==5) cout<<"debug"<<dp[cur][0]<<endl;
	for(int i=0;i<tree[cur].size();i++){
		dfs(tree[cur][i],cur,d+1);
	}
}
void ini(int rt){
	dfs(rt,-1,0);
	for(int k=1;k<=10;k++){
		for(int i=1;i<=n;i++){
			if(dp[i][k-1]<0){
				//cout<<"d"<<endl;
				dp[i][k]=-1;
			}
			else dp[i][k]=dp[dp[i][k-1]][k-1];
		}
	}
}
int LCA(int l,int r){
	//cout<<"start: "<<l<<" "<<r<<endl;
	if(depth[l]>depth[r]) swap(l,r);
	for(int i=0;i<=10;i++){
		//cout<<"debug ";
		if((depth[r]-depth[l]>>i)&1){
			//cout<<"debug: "<<r<<" ";
			r=dp[r][i];
			//cout<<r<<endl;
		}
	}
	//DEBUG
	//cout<<"hang: "<<l<<" "<<r<<endl;
	if(r==l) return l;
	for(int i=10;i>=0;i--){
		if(dp[r][i]!=dp[l][i]){//否则一起向上
			//cout<<"i: "<<i<<" "<<l<<" "<<r<<endl;
			l=dp[l][i];
			r=dp[r][i];
			//cout<<"after : "<<i<<" "<<l<<" "<<r<<endl;
		}
	}
	return dp[l][0];
}
int cmp(Node a,Node b){
	return a.id<b.id;
}
int main(){
	char ch;
	while(scanf("%d",&n)!=EOF){
		//cout<<"n= "<<n<<endl;
		for(int i=1;i<=n;i++) tree[i].clear();
		for(int i=0;i<=n;i++) {
			ans[i].id=i;
			ans[i].k=0;
		}
		memset(son,false,sizeof(son));
		for(int i=0;i<n;i++){
			int m,d,cnt=0;
			scanf("%d",&m);
			//cout<<m<<endl;
			scanf("%c",&ch);
			//cout<<ch<<endl;
			scanf("%c",&ch);
			//cout<<ch<<endl;
			scanf("%d",&cnt);
			//cout<<cnt<<endl;
			scanf("%c",&ch);
			//cout<<ch<<endl;
			for(int i=0;i<cnt;i++){
				scanf("%d",&d);
				tree[m].push_back(d);
				son[d]=1;
			}
		}
		int rt;
		for(int i=1;i<=n;i++){
			if(!son[i]){
				rt=i;
				break;
			}
		}
		ini(rt);
		scanf("%d",&Q);
		getchar();
		while(Q--)
		{
			while(getchar()!='(');
			scanf("%d%d",&l,&r);
			//cout<<"Q"<<endl;
			//cout<<l<<" "<<r<<endl;
			int d=LCA(l,r);
			//cout<<"d: "<<d<<endl;
			ans[d].k++;
			//ans[d].id=d;
			while(getchar()!=')');
		}
		//cout<<"-----------------------"<<endl;
		sort(ans+1,ans+n+1,cmp);

		for(int i=1;i<=n;i++){
		//	cout<<ans[i].k<<endl;
			if(ans[i].k){
		//		cout<<"ans: "<<endl;
				cout<<ans[i].id<<":"<<ans[i].k<<endl;
			}
		}
	}
	return 0;
}