http://codeforces.com/problemset/problem/766/D
题解:加权并查集
代码:
#include <iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<cstring>
using namespace std;
int p[100005],r[100005];
map<string,int>mp;
string s;
int finde(int x){
if(x==p[x])return x;
int y=finde(p[x]);
r[x]=(r[x]+r[p[x]])%2;
return p[x]=y;
}
bool join(int x,int y,int typ){
int xx,yy;
xx=finde(x);
yy=finde(y);
if(xx==yy){
if(typ==abs(r[x]-r[y]))return true;
return false;
}
p[xx]=yy;
r[xx]=(r[y]-r[x]+2+typ)%2;
return true;
}
int main()
{
int n,m,q;
int a,b,typ;
int i;
scanf("%d%d%d",&n,&m,&q);
for(i=0;i<n;i++){
cin>>s;
mp[s]=i;
p[i]=i;
r[i]=0;
}
for(i=0;i<m;i++){
scanf("%d",&typ);
cin>>s;
a=mp[s];
cin>>s;
b=mp[s];
typ--;
if(join(a,b,typ))printf("YES\n");
else printf("NO\n");
}
for(i=0;i<q;i++){
cin>>s;
a=mp[s];
cin>>s;
b=mp[s];
int aa,bb;
aa=finde(a);
bb=finde(b);
if(aa!=bb){
printf("3\n");
continue;
}
printf("%d\n",(r[a]-r[b]+2)%2+1);
}
// cout << "Hello world!" << endl;
return 0;
}