Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func newGraph(nNodes int) *Graph {
	g := Graph{}
	g.nodes = make([]*GraphNode, nNodes)
	for iNode := 0; iNode < len(g.nodes); iNode++ {
		g.nodes[iNode] = &GraphNode{}
		g.nodes[iNode].key = GraphNodeKey(iNode)
	}
	return &g
}

var infty = 1000000000

type GraphNodeKey int

// GraphNode is a node for undirected graph
type GraphNode struct {
	key       GraphNodeKey
	adjacents []*GraphNode
	visited   bool
	d, f      int
	parent    *GraphNode
	cc        int
}

func (g *Graph) setAdjacent(l, r GraphNodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

// Graph is a undirected graph
type Graph struct {
	nodes []*GraphNode
}

func (g *Graph) initialize() {
	for iNode := 0; iNode < len(g.nodes); iNode++ {
		g.nodes[iNode].visited = false
		g.nodes[iNode].d = infty
		g.nodes[iNode].f = infty
		g.nodes[iNode].parent = nil
		g.nodes[iNode].cc = -1 // 22.3-12
	}
}

type QueueEntry struct {
	node *GraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *GraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *Graph) {
	g.initialize()
	time = 0
	cc := 0

	for _, u := range g.nodes {
		if !u.visited {
			dfsVisit(g, u, cc)
			cc++
		}
	}
}

func dfsVisit(g *Graph, u *GraphNode, cc int) {
	time++
	u.d = time
	u.cc = cc

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v, cc)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nUsers := nextInt()
	nEdges := nextInt()
	graph := newGraph(nUsers)
	for iEdge := 0; iEdge < nEdges; iEdge++ {
		l := GraphNodeKey(nextInt())
		r := GraphNodeKey(nextInt())
		graph.setAdjacent(l, r)
		graph.setAdjacent(r, l)
	}

	fillDistancesByDepthFirstSearch(graph)

	nQueries := nextInt()
	for iQuery := 0; iQuery < nQueries; iQuery++ {
		l := GraphNodeKey(nextInt())
		r := GraphNodeKey(nextInt())

		// fmt.Println(graph.nodes[l].d, graph.nodes[r].d, graph.nodes[r].f, graph.nodes[l].f)
		if graph.nodes[l].cc == graph.nodes[r].cc {
			fmt.Println("yes")
		} else {
			fmt.Println("no")
		}
	}
}

Python: def dfs(u, color):
    global c
    global g
    s = [u]
    c[u] = color
    while 0 < len(s):
        ch = s.pop()
        for ch in g[ch]:
            u_c = c[ch]
            if u_c is None:
                c[ch] = color
                s.append(ch)

def colorize():
    global g
    global c
    global n
    color = 1
    for i in range(n):
        if c[i] == None:
            dfs(i, color)
            color += 1

n, m = list(map(int, input().split()))

g = [[] for i in range(n)]
for i in range(m):
    s, t = list(map(int, input().split()))
    g[s].append(t)
    g[t].append(s)

c = [None for i in range(n)]

colorize()

q = int(input())
for i in range(q):
    s, t = list(map(int, input().split()))
    if c[s] == c[t]:
        print("yes")
    else:
        print("no")

Python: # -*- coding: utf-8 -*-

def assignColor():
    C = [-1 for i in range(n)]
    for i in range(n):
        if C[i] == -1:
            C = BFS(i, C)
    return C

#@profile
def BFS(start, C):
    Q = [start]
    C[start] = start

    while len(Q) != 0:
        u = Q.pop(0)
        v = [i for i in G[u] if C[i] == -1] # v := ??£??\???????????????????????¢?´¢??????????????????
        
        for i in v:
            Q.append(i)
            C[i] = C[start]
    
    return C

def main():
    
    for i in range(m):
        s, t = list(map(int, input().split()))
        G[s].append(t)
        G[t].append(s)

    C = assignColor()
        
    q = int(input())
    
    for i in range(q):
        s, t = list(map(int, input().split()))
        if C[s] == C[t]:
            print("yes")
        else:
            print("no")
            
if __name__ == "__main__":
    n, m = list(map(int, input().split()))
    G = [[] for i in range(n)]

    main()

Python: n, m = map(int, input().split())

a = [[] for i in range(n)]

for i in range(m):
    com = list(map(int, input().split()))
    a[com[0]].append(com[1])
    a[com[1]].append(com[0])

q = int(input())

from collections import deque
for j in range(q):
    memo = [0 for i in range(n)]
    data = list(map(int, input().split()))
    memo[data[0]] = 1
    queue = deque(data[0])

    try:
        while len(queue):
            b = queue.popleft()
            for k in a[b]:
                if k == data[1]:
                    print("yes")
                    raise Exception
                if memo[k] == 0:
                    memo[k] = 1
                    queue.append(k)
        print("no")
    except Exception:
        pass

Python: n, m = map(int, input().split())
rootList = [-1] * n
 
def getRoot(x):
    if rootList[x] < 0:
        rootList[x] = x
        return x
    return getRoot(rootList[x])
 
 
def setSameRoot(x, y):
    x = getRoot(x)
    y = getRoot(y)
    if x != y:
        rootList[x], rootList[y] = min(x, y), min(x, y)
 
for i in range(m):
    s, t = map(int, input().split())
    setSameRoot(s, t)
q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    print("yes" if getRoot(s) == getRoot(t) else "no")

Python: def dfs(r, c):
    global color
    global g
    s = [r]
    color[r] = c
    while len(s) > 0:
        u = s.pop()
        for u in g[u]:
            v = color[u]
            if v is None:
                color[u] = c
                s.append(u)
                
def assigncolor():
    global g
    global color
    global n
    c = 1
    for i in range(n):
        if color[i] == None:
            dfs(i, c)
            c += 1
            
n, m = list(map(int, input().split()))

g = [[] for i in range(n)]
for i in range(m):
    s, t = list(map(int, input().split()))
    g[s].append(t)
    g[t].append(s)
    
color = [None for i in range(n)]

assigncolor()

q = int(input())
for i in range(q):
    if color[s] == color[t]:
        print("yes")
    else:
        print("no")

Python: import sys
def s():
 e=sys.stdin.readline
 n,m=map(int,e().split())
 P=[[]for _ in[0]*n]
 C=[0]*n
 k=0
 for _ in[0]*m:
  s,t=map(int,e().split());P[s]+=[t];P[t]+=[s]
 for i in range(n):
  k+=1
  if C[i]<1:
   s=[i];C[i]=k
   while s:
    u=s.pop()
    for v in P[u]:
     if C[v]<1:C[v]=k;s+=[v]
 for _ in[0]*int(e()):
  a,b=map(int,e().split())
  print(['no','yes'][C[a]==C[b]])
s()

Python: n_people, n_relationship = list(map(int, input().split()))
adj_list = [[] for _ in range(n_people)]
for i in range(n_relationship):
  p, target = list(map(int, input().split()))
  adj_list[p].append(target)
  adj_list[target].append(p)


group = [-1] * n_people
cnt = 0
for i in range(n_people):
  if group[i] == -1:
    group[i] = cnt
    stack = [i]
    while stack:
      at = stack.pop()
      for to in adj_list[at]:
        if group[to] == -1:
          group[to] = cnt
          stack.append(to)

    cnt += 1

for _ in range(int(input())):
    s, t = map(int, input().split())
    print('yes' if group[s] == group[t] else 'no')