Problem:
There is a cave.  The cave has N rooms and M passages. The rooms are numbered 1 to N, and the passages are numbered 1 to M. Passage i connects Room A_i and Room B_i bidirectionally. One can travel between any two rooms by traversing passages. Room 1 is a special room with an entrance from the outside.  It is dark in the cave, so we have decided to place a signpost in each room except Room 1. The signpost in each room will point to one of the rooms directly connected to that room with a passage.  Since it is dangerous in the cave, our objective is to satisfy the condition below for each room except Room 1.    * If you start in that room and repeatedly move to the room indicated by the signpost in the room you are in, you will reach Room 1 after traversing the minimum number of passages possible.  Determine whether there is a way to place signposts satisfying our objective, and print one such way if it exists.

Incorrect submission (verdict: Wrong Answer):
import heapq
from collections import deque
class Graph:
    def __init__(self,v,edgelist,w_v = None,directed = False):
        super().__init__()
        self.v = v
        self.w_e = [{} for _ in [0]*self.v]
        self.neighbor = [[] for _ in [0]*self.v]
        self.w_v = w_v
        self.directed = directed

        for i,j,w in edgelist:
            self.w_e[i][j] = w
            self.neighbor[i].append(j)

    def dijkstra(self,v_n):
        d = [float('inf')]*self.v
        d[v_n] = 0
        prev = [-1]*self.v

        queue = []
        for i,d_i in enumerate(d): heapq.heappush(queue,(d_i,i))
        
        while len(queue)>0:
            d_u,u = queue.pop()
            if d[u]<d_u :continue
            for v in self.neighbor[u]:
                alt = d[u]+self.w_e[u][v]
                if d[v]>alt:
                    d[v] = alt
                    prev[v] = u
                    heapq.heappush(queue,(alt,v))

        return d,prev

    def warshallFloyd(self):
        d = [[10**18]*self.v for _ in [0]*self.v]
        for i in range(self.v):
            d[i][i] = 0
            
        for i in range(self.v):
            for j in self.neighbor[i]:
                d[i][j] = self.w_e[i][j]
            
        for i in range(self.v):
            for j in self.neighbor[i]:
                d[i][j] = self.w_e[i][j]
        
        for k in range(self.v):
            for i in range(self.v):
                for j in range(self.v):
                    check = d[i][k] + d[k][j]
                    if d[i][j] > check:
                        d[i][j] = check
        return d

    def prim(self):
        gb = GraphBuilder(self.v,self.directed)

        queue = []
        for i,w in self.w_e[0].items(): heapq.heappush(queue,(w,0,i))
        rest = [True]*self.v
        rest[0] = False

        while len(queue)>0:
            w,i,j = heapq.heappop(queue)
            if rest[j]:
                gb.addEdge(i,j,w)
                rest[j] = False
                for k,w in self.w_e[j].items():
                    if rest[k]:
                        heapq.heappush(queue,(w,j,k))

        return gb

    def bfs(self,vartex = 0):
        todo = [True]*self.v
        queue = deque([vartex])
        while(len(queue)>0):
            v = queue.popleft
            todo[v] = False
            yield v
            for v_i in self.neighbor[v]:
                if todo[v_i]:
                    queue.append(v_i)

    def dfs(self,vartex = 0):
        seen = [False]*self.v
        def recdfs(v):
            seen[vartex] = True
            for next_v in self.neighbor[vartex]:
                if (seen[next_v]):continue
                recdfs(next_v)
    
        
            
class Tree():
    def __init__(self,v,e):
        pass

class GraphBuilder():
    def __init__(self,v,directed = False,edge = None, weights = None):
        self.v = v
        self.directed = directed
        self.edge = []
        self.weights = []
        if edge is not None:
            self.addEdges(edge)
        if weights is not None:
            self.addVartex(weights)

    def addEdge(self,i,j,w=1):
        if not self.directed:
            self.edge.append((j,i,w))
        self.edge.append((i,j,w))

    def addEdges(self,edgelist,weight = True):
        if weight:
            if self.directed:
                for i,j,w in edgelist:
                    self.edge.append((i,j,w))
            else:
                for i,j,w in edgelist:
                    self.edge.append((i,j,w))
                    self.edge.append((j,i,w))
        else:
            if self.directed:
                for i,j in edgelist:
                    self.edge.append((i,j,1))
            else:
                for i,j in edgelist:
                    self.edge.append((i,j,1))
                    self.edge.append((j,i,1))
    
    def addVartex(self,weights):
        if len(weights) != self.v:
            return
        self.weights.extend(weights)

    def addAdjMat(self, mat):
        for i,mat_i in enumerate(mat):
            for j,w in enumerate(mat_i):
                self.edge.append((i,j,w))

    def buildTree(self):
        pass

    def buildGraph(self):
        return Graph(self.v,self.edge,directed=self.directed)

def main():
    n,m = tuple([int(t)for t in input().split()])
    edge = []

    for i in range(m):
        a,b = tuple([int(t)for t in input().split()])
        edge.append((a-1,b-1,1))

    gb = GraphBuilder(n,edge=edge)
    g = gb.buildGraph()

    queue = deque([0])
    root = [-1]*n
    checked = [False]*n
    while(len(queue)>0):
        p = queue.popleft()
        if checked[p]:
            continue
        checked[p] = True
        for q in g.neighbor[p]:
            root[q] = p+1
            queue.append(q)

    if all(checked):
        print("Yes")
        for i in root[1:]:
            print(i)

if __name__ == "__main__":
    main()

Fixed, accepted submission:
import heapq
from collections import deque
class Graph:
    def __init__(self,v,edgelist,w_v = None,directed = False):
        super().__init__()
        self.v = v
        self.w_e = [{} for _ in [0]*self.v]
        self.neighbor = [[] for _ in [0]*self.v]
        self.w_v = w_v
        self.directed = directed

        for i,j,w in edgelist:
            self.w_e[i][j] = w
            self.neighbor[i].append(j)

    def dijkstra(self,v_n):
        d = [float('inf')]*self.v
        d[v_n] = 0
        prev = [-1]*self.v

        queue = []
        for i,d_i in enumerate(d): heapq.heappush(queue,(d_i,i))
        
        while len(queue)>0:
            d_u,u = queue.pop()
            if d[u]<d_u :continue
            for v in self.neighbor[u]:
                alt = d[u]+self.w_e[u][v]
                if d[v]>alt:
                    d[v] = alt
                    prev[v] = u
                    heapq.heappush(queue,(alt,v))

        return d,prev

    def warshallFloyd(self):
        d = [[10**18]*self.v for _ in [0]*self.v]
        for i in range(self.v):
            d[i][i] = 0
            
        for i in range(self.v):
            for j in self.neighbor[i]:
                d[i][j] = self.w_e[i][j]
            
        for i in range(self.v):
            for j in self.neighbor[i]:
                d[i][j] = self.w_e[i][j]
        
        for k in range(self.v):
            for i in range(self.v):
                for j in range(self.v):
                    check = d[i][k] + d[k][j]
                    if d[i][j] > check:
                        d[i][j] = check
        return d

    def prim(self):
        gb = GraphBuilder(self.v,self.directed)

        queue = []
        for i,w in self.w_e[0].items(): heapq.heappush(queue,(w,0,i))
        rest = [True]*self.v
        rest[0] = False

        while len(queue)>0:
            w,i,j = heapq.heappop(queue)
            if rest[j]:
                gb.addEdge(i,j,w)
                rest[j] = False
                for k,w in self.w_e[j].items():
                    if rest[k]:
                        heapq.heappush(queue,(w,j,k))

        return gb

    def bfs(self,vartex = 0):
        todo = [True]*self.v
        queue = deque([vartex])
        while(len(queue)>0):
            v = queue.popleft
            todo[v] = False
            yield v
            for v_i in self.neighbor[v]:
                if todo[v_i]:
                    queue.append(v_i)

    def dfs(self,vartex = 0):
        seen = [False]*self.v
        def recdfs(v):
            seen[vartex] = True
            for next_v in self.neighbor[vartex]:
                if (seen[next_v]):continue
                recdfs(next_v)
    
        
            
class Tree():
    def __init__(self,v,e):
        pass

class GraphBuilder():
    def __init__(self,v,directed = False,edge = None, weights = None):
        self.v = v
        self.directed = directed
        self.edge = []
        self.weights = []
        if edge is not None:
            self.addEdges(edge)
        if weights is not None:
            self.addVartex(weights)

    def addEdge(self,i,j,w=1):
        if not self.directed:
            self.edge.append((j,i,w))
        self.edge.append((i,j,w))

    def addEdges(self,edgelist,weight = True):
        if weight:
            if self.directed:
                for i,j,w in edgelist:
                    self.edge.append((i,j,w))
            else:
                for i,j,w in edgelist:
                    self.edge.append((i,j,w))
                    self.edge.append((j,i,w))
        else:
            if self.directed:
                for i,j in edgelist:
                    self.edge.append((i,j,1))
            else:
                for i,j in edgelist:
                    self.edge.append((i,j,1))
                    self.edge.append((j,i,1))
    
    def addVartex(self,weights):
        if len(weights) != self.v:
            return
        self.weights.extend(weights)

    def addAdjMat(self, mat):
        for i,mat_i in enumerate(mat):
            for j,w in enumerate(mat_i):
                self.edge.append((i,j,w))

    def buildTree(self):
        pass

    def buildGraph(self):
        return Graph(self.v,self.edge,directed=self.directed)

def main():
    n,m = tuple([int(t)for t in input().split()])
    edge = []

    for i in range(m):
        a,b = tuple([int(t)for t in input().split()])
        edge.append((a-1,b-1,1))

    gb = GraphBuilder(n,edge=edge)
    g = gb.buildGraph()

    queue = deque([0])
    root = [-1]*n
    checked = [False]*n
    determined = [False]*n
    while(len(queue)>0):
        p = queue.popleft()
        if checked[p]:
            continue
        checked[p] = True
        for q in g.neighbor[p]:
            if determined[q]:
                continue 
            root[q] = p+1
            queue.append(q)
            determined[q] = True

    if all(checked):
        print("Yes")
        for i in root[1:]:
            print(i)
    else:
        print("No")

if __name__ == "__main__":
    main()