P2256 一中校運會之百米跑

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思路：

#include<bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;
#define ll long long     

map<string,string>f;
string find(string x)
{
  if(f[x] != x)
  return f[x] = find(f[x]);
  return f[x];
}
int main()
{
  int n,m;
  scanf("%d%d",&n,&m);
  for(int i = 1; i <= n; i++)
  {
    string a;
    cin>>a;
    f[a] = a;
  }
  while(m--)
  {
    string a,b;
    cin>>a>>b;
    f[find(a)] = f[find(b)];
  }
  int k;
  cin>>k;
  while(k--)
  {
    string a,b;
    cin>>a>>b;
    if(f[find(a)] == f[find(b)])
    printf("Yes.\n");
    else
    printf("No.\n");
  }
}