Problem:
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Connected Components

Write a program which reads relations in a SNS (Social Network Service), and judges that given pairs of users are reachable each other through the network.

Input

In the first line, two integer $n$ and $m$ are given. $n$ is the number of users in the SNS and $m$ is the number of relations in the SNS. The users in the SNS are identified by IDs $0, 1, ..., n-1$.

In the following $m$ lines, the relations are given. Each relation is given by two integers $s$ and $t$ that represents $s$ and $t$ are friends (and reachable each other).

In the next line, the number of queries $q$ is given. In the following $q$ lines, $q$ queries are given respectively. Each query consists of two integers $s$ and $t$ separated by a space character.

Output

For each query, print "yes" if $t$ is reachable from $s$ through the social network, "no" otherwise.

Constraints

$2 \leq n \leq 100,000$

$0 \leq m \leq 100,000$

$1 \leq q \leq 10,000$

Sample Input

10 9
0 1
0 2
3 4
5 7
5 6
6 7
6 8
7 8
8 9
3
0 1
5 9
1 3

Sample Output

yes
yes
no

Solution in C (judge verdict: Accepted)

#include<stdio.h>
int pop(void);
void push(int);
void enqueue(int,int);
int dequeue(int);
void assigncolor(void);
void DFS(int,int);

int n;
int head[100000],tail[100000];
int Q[100000][100];
int C[100000];
int size=0,S[100000];

int main(){
  int i;
  int m,s,t,q;
  scanf("%d%d",&n,&m);
  for(i=0;i<m;i++){
    scanf("%d%d",&s,&t);
    enqueue(s,t);
    enqueue(t,s);
  }
  assigncolor();
  scanf("%d",&q);
  int qs[q],qt[q];
  for(i=0;i<q;i++){
    scanf("%d%d",&qs[i],&qt[i]);
  }
  for(i=0;i<q;i++){
    if(C[qs[i]]==C[qt[i]]){
      printf("yes\n");
    }
    else{
      printf("no\n");
    }
  }
  return 0;
}
int pop(void){
  size--;
  return S[size];
}
void push(int n){
  S[size]=n;
  size++;
}
void enqueue(int s,int t){
  
  Q[s][tail[s]]=t;
  if(tail[s]+1==100){
    tail[s]=0;
  }
  else{
    tail[s]++;
  }
}

int dequeue(int s){

  int n;

  n=Q[s][head[s]];
  if(head[s]+1==100){
    head[s]=0;
  }
  else{
    head[s]++;
  }
  return n;
}

void assigncolor(void){
  int i;
  int id=1;
  for(i=0;i<n;i++){
    C[i]=-1;
  }
  for(i=0;i<n;i++){
    if(C[i]==-1){
      DFS(i,id++);
    }
  }
}

void DFS(int r,int c){
  int i;
  int u,v;
  push(r);
  C[r]=c;
  while(size!=0){
    u=pop();
    for(i=0;i<tail[u]-head[u];i++){ 
      v=Q[u][i];
      if(C[v]==-1){
	C[v]=c;
	push(v);
      }
    }
  }
}