题目连接：
http://codeforces.com/contest/766/problem/D
Description
Mahmoud wants to write a new dictionary that contains n words and relations between them. There are two types of relations: synonymy (i. e. the two words mean the same) and antonymy (i. e. the two words mean the opposite). From time to time he discovers a new relation between two words.
He know that if two words have a relation between them, then each of them has relations with the words that has relations with the other. For example, if like means love and love is the opposite of hate, then like is also the opposite of hate. One more example: if love is the opposite of hate and hate is the opposite of like, then love means like, and so on.
Sometimes Mahmoud discovers a wrong relation. A wrong relation is a relation that makes two words equal and opposite at the same time. For example if he knows that love means like and like is the opposite of hate, and then he figures out that hate means like, the last relation is absolutely wrong because it makes hate and like opposite and have the same meaning at the same time.
After Mahmoud figured out many relations, he was worried that some of them were wrong so that they will make other relations also wrong, so he decided to tell every relation he figured out to his coder friend Ehab and for every relation he wanted to know is it correct or wrong, basing on the previously discovered relations. If it is wrong he ignores it, and doesn't check with following relations.
After adding all relations, Mahmoud asked Ehab about relations between some words based on the information he had given to him. Ehab is busy making a Codeforces round so he asked you for help.
Input
The first line of input contains three integers n, m and q (2 ≤ n ≤ 105, 1 ≤ m, q ≤ 105) where n is the number of words in the dictionary, m is the number of relations Mahmoud figured out and q is the number of questions Mahmoud asked after telling all relations.
The second line contains n distinct words a1, a2, ..., an consisting of small English letters with length not exceeding 20, which are the words in the dictionary.
Then m lines follow, each of them contains an integer t (1 ≤ t ≤ 2) followed by two different words xi and yi which has appeared in the dictionary words. If t = 1, that means xi has a synonymy relation with yi, otherwise xi has an antonymy relation with yi.
Then q lines follow, each of them contains two different words which has appeared in the dictionary. That are the pairs of words Mahmoud wants to know the relation between basing on the relations he had discovered.
All words in input contain only lowercase English letters and their lengths don't exceed 20 characters. In all relations and in all questions the two words are different.
Output
First, print m lines, one per each relation. If some relation is wrong (makes two words opposite and have the same meaning at the same time) you should print "NO" (without quotes) and ignore it, otherwise print "YES" (without quotes).
After that print q lines, one per each question. If the two words have the same meaning, output 1. If they are opposites, output 2. If there is no relation between them, output 3.
See the samples for better understanding.
Sample Input
3 3 4
hate love like
1 love like
2 love hate
1 hate like
love like
love hate
like hate
hate like
Sample Output
YES
YES
NO
1
2
2
2
Hint
题意
给你n个串，然后给你m个关系，p个询问。
每个关系告诉你两个单词是同义还是反义的，如果与之前的不矛盾的话，输出yes；如果矛盾，就忽略这次操作，输出no。
对于每个询问，如果两个单词是同义输出1，反义输出2，不知道输出3.
题解：
经典老题了，POJ食物链。
我们用并查集去做，让2i表示这个词，2i-1表示这个词的反义。
如果i和j同义，就说明2i和2j一样，2i-1和2j-1一样。
如果反义，就说明2i-1和2j一样，2i和2j-1一样。
然后check就好了。
代码
#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e6+7;
int n,m,p;
string s[maxn];
map<string,int> H;
int fa[maxn];
int fi(int x){
return fa[x]==x?x:fa[x]=fi(fa[x]);
}
void uni(int x,int y){
x=fi(x),y=fi(y);
if(x==y)return;
fa[x]=y;
}
int main()
{
scanf("%d%d%d",&n,&m,&p);
for(int i=1;i<=2*n;i++)
fa[i]=i;
for(int i=1;i<=n;i++){
cin>>s[i];
H[s[i]]=i;
}
for(int i=1;i<=m;i++){
int op;
string a,b;
cin>>op>>a>>b;
int id1=H[a],id2=H[b];
if(op==1){
if(fi(id1*2)==fi(id2*2-1)){
cout<<"NO"<<endl;
continue;
}
if(fi(id1*2-1)==fi(id2*2)){
cout<<"NO"<<endl;
}
cout<<"YES"<<endl;
uni(id1*2,id2*2);
uni(id1*2-1,id2*2-1);
}else{
if(fi(id1*2)==fi(id2*2)){
cout<<"NO"<<endl;
continue;
}
if(fi(id1*2-1)==fi(id2*2-1)){
cout<<"NO"<<endl;
}
cout<<"YES"<<endl;
uni(id1*2,id2*2-1);
uni(id1*2-1,id2*2);
}
}
for(int i=1;i<=p;i++){
string a,b;
cin>>a>>b;
int id1=H[a],id2=H[b];
if(fi(2*id1)==fi(2*id2))
cout<<"1"<<endl;
else if(fi(2*id1-1)==fi(2*id2-1))
cout<<"1"<<endl;
else if(fi(2*id1-1)==fi(2*id2))
cout<<"2"<<endl;
else if(fi(2*id1)==fi(2*id2-1))
cout<<"2"<<endl;
else
cout<<"3"<<endl;
}
}